Shulou(Shulou.com)06/02 Report--

General technical problems of computer hardware and software

Mastering the general operation of the computer operating system and the knowledge of software and hardware operation and maintenance as well as the use of general tools can make us more comfortable in solving daily technical problems (up-to-date). Loop reflex

one。 Windows system operation problems:

1.1 View system activation status

Run enter the "slmgr.vbs-xpr" command to see if the system is permanently activated

Run enter the "slmgr.vbs-dlv" command to display the most detailed activation information.

1.2 computer group policy issues:

Group Policy (Group Policy) is the primary tool for Microsoft Windows system administrators to define and control programs, network resources, and operating system behavior for users and computers. You can set a variety of software, computer, and user policies by using Group Policy. The registry is a database that saves the configuration of system software and application software in the Windows system, and with more and more Windows functions, there are more and more configuration items in the registry, and many configurations can be customized, but these configurations are distributed in every corner of the registry. If it is manual configuration, you can imagine how difficult and complicated it is. On the other hand, the group policy integrates the important configuration functions of the system into various configuration modules for users to use directly, so as to achieve the purpose of convenient management of the computer. In a nutshell, Group Policy settings are modifying the configuration in the registry. Of course, group policy uses a more perfect method of management and organization, which can manage and configure the settings in various objects, which is far more convenient, flexible and powerful than manually modifying the registry.

Computer Group Policy-Local computer Policy is divided into computer configuration and user configuration. Computer configuration is a group policy configuration that takes effect globally for the local computer, and user configuration is a group policy configuration that is valid only for the current user.

1.3 the login interface appears after the Windows system starts. How to cancel the login interface and go directly to the operating system:

Enter "control userpasswords2" in the command prompt interface and uncheck "to use this computer, the user must enter a user name and password (E)", as shown in figure {Note: if the current user and all other users are cleared in the "local user" list in the following figure, these users will be disabled [they will not be able to enter the system because there is no login user option next time the system is restarted] At this point, you need to click "Advanced" in the "Advanced" dialog box, then click "user → wants to enable users" in the pop-up "lusrmgr- [Local users and groups (Local)\ users] dialog box, then right open the user's" Properties "dialog box, uncheck the" account disabled "option, and click" OK "to save the settings. You can also enter "lusrmgr.msc (Local User Management and Group)" in "run" to open the "lusrmgr- [Local users and groups (Local)\ users]" dialog box, and then undisable the users that still need to be used}:

Then click "apply" or "OK" and pop up a dialog box for the computer to specify the login user, as follows:

Enter the user name (the local user name that is currently logged in by default), you can log in with that user by default the next time you enter the system without popping up the login interface.

1.4 how to switch logged-in users of shared files:

Usually, the dialog box of "enter Network credentials" pops up when you access the shared file for the first time.

After entering the correct "user name" and "password", you can access the shared file, but sometimes the currently logged-in user does not have enough access to some files, so you need to switch login users. There are two ways to switch between shared file login users: the first is "Control Panel → user account → credential Manager → manages Windows credentials → to delete or modify corresponding credentials", and then revisit the shared file. Enter the user name and password you need to log in (if you are modifying Windows credentials, change the credentials to the required login user name and password, and then directly access the shared file without authentication login window)

The second is the way the command prompt window executes the command. Using the "net use" command, execute the "net use" command at the command prompt window to view all current connections. If not, it will prompt that the list of network connections is empty.

Enter "net use\ computer name or IP address / user: username" command to log in with the specified username

Enter the correct corresponding password to complete the authorized access connection, and then you can directly access the shared file.

Execute the "net use / del" or "net use / delete" command to delete the network connection and its credentials saved by the current operating system, while "net use / del / Y" or "net use / delete / y" delete directly without confirmation.

Execute the "net use\ computer name or IP address / del / y" command to delete the specified computer name or IP address network connection and its credentials (note: to ensure that the network connection and credentials for accessing the shared file are saved in the current operating system, that is, the prompt is not blank when executing the "net use" command)

Executing the "net use\ computer name or IP address\ ipc$" / user: "" command establishes an empty connection to the specified computer name or IP address host (Note: the host to the specified computer name or IP address cannot have any other network connections, or delete all links in advance, otherwise the command cannot be executed), such a network connection will prompt you to be unable to access shared resources with permissions.

1.5 how to quickly jump to the Startup folder of the Windows operating system:

Press the keyboard shortcut key "Windows+R", enter the "shell:startup" command and execute, you can jump to the operating system "startup" folder, or enter the full path "C:\ ProgramData\ Microsoft\ Windows\ Start Menu\ Programs\ StartUp" in Windows Explorer to navigate to the system "boot" folder. Once you open the Startup folder, you can modify, add, or delete boot entries for the operating system.

two。 Technical problems in the general operation of computers:

1.1 Keymouse cannot be identified by computer for cause screening:

USB ports are disabled, interruption request (IRQ) conflicts, power supply instability (there may be power-on self-test (Power On Self Test), that is, keyboard and mouse can be used before POST, but can not be used after entering the operating system interface; or some USB ports can be used but some cannot; or all USB ports cannot be used), look at whether the keyboard and mouse lights are on, you can know whether the keyboard or mouse is powered. USB interface standard problems, such as some keyboard and mouse devices are not supported by the USB 3.0 standard.

1.2 HDMI interface supports hot plug, DVI interface also supports hot plug, but VGA interface does not support hot plug (but the latest VGA interface seems to support hot plug).

1.3 unable to connect to the printer, the printer cannot print:

Generally, it is a software problem, if it is a software problem, modify the settings if it is easy to solve, delete the original printer directly if it is not easy to solve, select the corresponding driver, and add the printer again. When you cannot add a newly set shared printer by adding a network printer, choose to add the printer by name, enter the correct location and the printer's share name, and then add it successfully. Add some settings for shared printers: open the Properties dialog box of the network adapter and check "Microsoft Network clients" and "File and Printer sharing on Microsoft Networks" or click "install" to add these two items, unenable Guest users, Modify "Local computer Policy → computer configuration → Windows Settings → Security Settings → Local Policy → Security options → Network access: sharing of Local accounts and Security Model" to "Classic …" Modify the control panel → system and security → management tools → local security policy → security settings → local policy → security options → account: guest account status → disabled or right-click "this computer" and click "manage → computers manage (local) → local users and groups → users → Guest built-in account → (checked) account disabled for guests to access computers or domains" setting to disable guest accounts Modify the Control Panel → user accounts → user accounts → manage other accounts → add new users → other users → add others to this computer settings add password-free users or unenable "Guest" users. Some printers need to provide a user name and password to access normally, at this time, please check whether the rights management of the printer is configured with the correct account and password, whether it is consistent with the account established on the printer device, or other print rights issues (such as some companies' printer black and white / color settings need to be consistent with the settings on the print properties of the user's computer).

Note: too little remaining space on the hard disk will also cause the printer to fail to print. Please check whether the free space on the hard disk is lower than 10MB. If the remaining space on the hard disk is lower than 10MB, you must empty the Recycle Bin, delete temporary files on the hard disk, delete expired files or archived files on the hard disk, delete programs that are never used, and free up more space before printing. To check that the printer cable is plugged in securely, you must make sure that both ends of the cable connecting the computer and the printer are plugged in securely. If you use a printer switching device (such as a parallel port scanner, printer sharer), connect the printer directly to the computer without switching the device, and then try to print. If you can print normally without switching devices, it means that there is a problem with the switching device; check whether the printer port in BIOS is open, the printer port in BIOS should be set to Enable, and note that some early printers do not support ECP type print port signal, then you should set the print port to Normal, SPP, ECP+EPP mode to try.

1.4 issues with shared printers that can only be accessed by some computer connections:

Most of the computers that cannot be accessed are because they are not granted sufficient access rights (permissions granted by the host that shares the printer, permissions granted by the local operating system of the remote computer that needs to connect to the shared printer), the access rights of the shared devices or files of the shared host are set to "Everyone", and the local operating system of the remote computer gives the remote computer sufficient access rights. For example, check "enable Network Discovery", "enable File and Printer sharing" and "turn off password protected sharing" in the Advanced sharing Settings of the Network and sharing Center, or change the corresponding items to the necessary values in the Local Group Policy Editor and Local users and groups (i.e., lusrmgr- [Local users and groups (Local)\ users]).

1.5 the driver cannot be installed properly when adding the printer, and there is an exclamation point on the printer icon after it is added.

In the Windows7 system, this situation occurs because the "Print Spooler" service is not started, set the startup type of the service to "automatic" and start, you can add and install the printer normally; sometimes because the system is cut out, the system lacks files such as "unidrv.hlp" needed to install the printer, add the missing files and install normally. In Windows8 and Windows10 systems, sometimes because of the problem of "forced driver signature", unverified signed drivers are not allowed to be installed, which leads to the failure of installing drivers when adding printers. The problem can be solved by turning off "forced driver signatures". In Windows10 systems, the method to close is to click "notify", enter and find "all settings" and open it. In the pop-up "Settings" dialog box, select the "Update and Security" tab and open it, find "restore" in the "Update and Security" tab, click "restart now" under "Advanced Startup", find "troubleshooting" in the pop-up interface and open it, select "Advanced options-> Startup Settings-> restart", and press the prompt to enter "7" to disable the driver's forced signature. In the Windows8 system, because Microsoft separates the hardware device management service in Windows8.1 and forces the driver signature authentication, if the relevant service is not turned on when installing the driver, it is likely to pop up error messages such as "invalid data" and "printer installation failure". Then enter the "services.msc" command in the shortcut key "Windows+R" to open the "Services" tab. Find the "Device Install Service" and "Device Setup Manager" services and enable them, then press the shortcut key "Windows+R" and enter "shutdown.exe / r / o / f / t 00", select "troubleshooting-> Advanced-> Startup Settings-> restart", and select "Disable Driver Signature Forcement" in the safe mode list to disable driver signature mandatory authentication to solve the problem.

1.6 the printer is in a normal state but does not produce paper when printing

When looking at the print queue, I found that it either prompted an error or existed for a long time or disappeared for a long time, which is generally due to the problems caused by the wrong printer port selection, such as COM port or LPT port, and the printer is actually connected to the USB port, then it must not be able to drive the printer, thus unable to print.

Additional knowledge about printer port: Line Print Terminal abbreviation, LPT,LPT interface (parallel port) is generally used to connect printers or scanners, is an enhanced two-way parallel transmission interface, before the emergence of USB interface is the most commonly used interface for scanners and printers, the highest transmission speed is 1.5Mbps, the equipment is easy to install and use, but the speed is relatively slow COM port is also a printer interface, COM interface is used for needle printers and laser printers, but laser printers also have USB interface, COM port is a multi-function port, can also connect game consoles, mice (old-fashioned) and other devices, printers can also connect to USB interface, USB interface is usually used on inkjet printers. The longest at the back of the chassis is the LPT port, which is full of pinhole jacks, that is, the female head; the shorter one is the COM port, which is all protruding pinhole, that is, the male head. Now, printers use USB interface most, because the transmission speed of USB interface is much faster than LPT and COM port!

Note: some instructions for local and network printers

The local printer only needs to install the driver correctly and select the correct printer port, and you can basically print, but if it is a network printer, it involves the configuration of the printer server host (the host that directly connects to the printer and provides the shared printer) and the client host (the host connected to the shared printer through the network). In addition to correctly installing the driver, the printer server also needs to install and configure the File and Printer sharing Protocol, and share the directly connected printers to the network for the client host to print. The printer client host also needs to install the driver correctly and install the configuration "File and Printer sharing Protocol" at the same time, whether it is the printer client or the server host, the step is to install the driver to add the printer after installing and configuring the protocol.

1.7 troubleshooting of network connectivity problems:

The first step is to enter "ping 127.0.0.1-t" in the command prompt interface to see if you can ping. The command is the ping network loopback address. If ping fails, you need to reinstall the TCP/IP protocol.

The second step is to ping the IP address of the local host in the command prompt interface. If the ping is not accessible, it means that there is a problem with the host network card, and the network card driver needs to be reinstalled.

Third, in the command prompt interface, the IP address of the ping gateway (router) (such as 192.168.1.1). If the ping is not available, it means that the host is malfunctioning to the routed network.

The fourth step, in the command prompt interface ping remote server (such as "ping www.baidu.com"), if it can be reached, it means that the remote physical network is good, if not, contact the telecom network operator to solve the network failure that can not access the remote Internet.

The above four steps are standard steps for diagnosing and troubleshooting the cause of a network failure.

Note: the ping (Internet packet Explorer, Packet Internet Groper) command uses the ICMP protocol (Internet message Control Protocol Internet Control Messages Protocol). Ping sends an ICMP packet, sends an echo request message to the destination host and reports whether it has received the desired ICMP Echo (ICMP echo response). It is a command used to check whether the network is unblocked or the network connection speed, therefore, in order to eliminate the ping failure caused by the inbound rules of the firewall You should modify the advanced settings of Windows firewall, switch to the "Advanced Security Windows Firewall" window, and select "inbound Rule Inbound Rules", specifically "File and Printer Sharing (Echo Request-ICMPv4-In)" under all networks (public Public, domain Domain, private Private networks) with IPv4 or IPv6 versions enabled, as shown in the figure.

1.8 the difference between "workgroups" and "domains" of computers:

Working group (Work Group) is a concept in the local area network, it is the most common, simplest and most common resource management mode, that is, different computers are included in different groups according to their functions to facilitate management. A working group is a group of many users who are in the same physical location and connected by the same local area network; accordingly, a working group can also be a logical group of users all over the same organization but connected by the same network. In both cases, users in the workgroup can share system resources such as applications, e-mails, documents, and so on in a predefined way. A workgroup can be a simple user group with the same name, on the other hand, the workgroup can have some privileges on its network, such as access to file servers or special applications.

Domain (Domain) is an independent unit in Windows network. Mutual access between domains requires the establishment of trust relationship (that is, Trust Relation). Trust relationship is the bridge between domains. When a domain establishes a trust relationship with other domains, the two domains can not only manage each other as needed, but also distribute device resources such as files and printers across the network, so as to realize the sharing and management of network resources between different domains. and mutual communication and data transmission. Domain is not only the logical organization unit of Windows network operating system, but also the logic organization unit of Internet. In Windows network operating system, domain is the security boundary. A domain administrator can only manage the interior of a domain and cannot access or manage other domains unless other domains are explicitly granted administrative rights. Each domain has its own security policy and its security trust relationship with other domains.

The principle of the domain: in fact, you can connect the domain and the workgroup to understand that all settings on the workgroup are carried out on the local computer, including various policies, the user login is also logged on to the local computer, and the password is verified in the local database. If the computer joins the domain, the various policies are set uniformly by the domain controller, and the user name and password are also put into the domain controller to verify, that is to say, an account password can be logged on to any computer in the same domain. The domain controller contains a database of information such as accounts, passwords, computers belonging to the domain, and so on. When a computer is connected to the network, the domain controller first needs to identify whether the computer belongs to the domain, whether the login account used by the user exists and whether the password is correct, and if any of the above information is incorrect, then the domain controller will refuse the user to log in from this computer. A working group is a collection of computers. It is only a logical collection, and each computer is managed separately. If you want to access the computer in it, you still have to authenticate the user on the computer being visited. Different from the domain, the domain is a collection of computers with security boundaries. Computers in the same domain have established a trust relationship with each other, and access to other machines in the domain is no longer required. Because when joining the domain, the administrator establishes a computer account for each computer in the domain (but not in the same domain as the user), which is the same as the user account There is also password protection, which is called login credentials in the domain and is issued and maintained by the KDC service on the DC (domain controller) of Windows Server 2000. In order to ensure the security of the system, the KDC service will automatically update all the credentials every 30 days and record the last (most recent) credentials. Over and over again, the server will always keep 2 credentials, which are valid for 60 days. After 60 days, the last used credentials will be discarded by the system. If the credentials in the Ghost backup are 60 days old, the computer restored using the backup will not be authenticated by the KDC service, and any access requests (including login) on this computer will be prohibited. The simple solution is to detach the computer from the domain and rejoin, the KDC service will reset this credential, or use the NETDOM command in the Windows Server 2000 resource bundle to force the security credentials to be reset. Therefore, in the existing domain environment, try not to use Ghost to back up the system partition after the computer joins the domain. If the backup is done, please confirm that the backup is done within 60 days. If it exceeds, it is best to contact the system administrator and let the administrator reset the computer security credentials, otherwise you will not be able to log in to the domain environment.

The domain is different from the environment applicable to the workgroup. The domain is generally used in a larger network, while the workgroup is smaller. You need a server-like computer in a domain, called a domain control server. If other computers want to access each other, first of all, they all go through it. But the working group is different. All computers in a working group are peer-to-peer, that is, there is no distinction between servers and clients, but like a domain, if a computer wants to access other computers, we must first find a computer in this group that is similar to a group control server. Such a group control server is not fixed and is implemented by election. It stores the relevant information of this group. Find this computer and get the information about the group, and then access other computers in the group.

(2) the direct connection and cross lines of the network connection cable (network cable)

First, understand the various wire concepts defined by the core wire sequence of different network wires:

Cross line: 568A standard on one end and 568B standard on the other.

Direct connection: either the 568A standard or the 568B standard, that is, the wire sequence of both ends is the same.

Reverse lines: one end can be 568A standard, or 568B standard, and the other end should be in the opposite direction. For example, the order of 568A standard lines is: green-white, green, orange-white, blue-white, blue-white, orange, brown-white, brown-white, then the other line should be brown, brown-white, orange-white, blue-white, blue-white, green-white, green-white.

The wiring standard of EIA/TIA specifies the wire sequence of two kinds of twisted pair-568A and 568B standards:

Standard 568A line order: 1-green, 2-green, 3-orange-white, 4-blue, 5-blue-white, 6-orange, 7-brown-white, 8-brown

Standard 568B line order: 1-orange-white, 2-orange, 3-green-white, 4-blue, 5-blue-white, 6-green, 7-brown-white, 8-brown.

8P8C, also known as RJ-45 connector, is a common connector plug when Ethernet is connected by twisted pair. The meaning of 8P8C is: 8 Position (8 grooves) and 8 Contact (8 metal contacts).

The network cable of 10m Ethernet only uses the core wires numbered 1, 2, 3 and 6 to transmit data, that is, 1 and 2 are used for sending, 3 and 6 are used for receiving, and orange, white and orange are used for sending according to color. Green, white and green are used for receiving, and 4, 5, 7 and 8 are two-way lines. 100m and 1000m network cards need to use four pairs of wires, that is, all eight core wires are used to transmit data. Because the 10m network card can use the network cable made according to 100m mode, and the twisted pair cable provides four pairs of wires, it is no longer distinguished in daily life. 10m network card generally makes network cable according to 100m mode. In 100 megabit Ethernet, only 1, 2, 3, 6 four-wire differential signal transmission mode can be used to reduce electromagnetic interference, in which 1 and 2 are twisted together for TX (transmission) and 3 and 6 are twisted together for RX (receiving). In Gigabit Ethernet or Power over Ethernet, all four pairs of differential lines are used. Orange-white and orange constitute a pair of differential transmission lines, green-white and green form a pair of differential transmission lines, blue-white and blue form a pair of differential transmission lines, and brown-white and brown form a pair of differential transmission lines.

In practice, it is generally understood as follows:

① uses crossover connections between devices of the same type, and straight-through connections between different types of devices.

② routers and PC belong to DTE (data terminal equipment) type devices, switches and HUB belong to DCE (data communication equipment) type devices

③ RJ-45 network connector generally has 568A and 568B two methods, according to the same standard is straight line, different standard is cross line, no matter how to connect, after the final completion of the RJ-45 line tester test, 8 lights should be sequentially flashed.

Third, the use of general tools and software:

1 Wireshark

Wireshark (formerly known as Ethereal) is a network packet analysis software. The function of network packet analysis software is to capture network packets and show the most detailed network packet data as much as possible. Wireshark uses WinPcap as the interface to exchange data messages directly with the network card.

The author recently installed the latest "Wireshark-win64-2.6.1" on the Windows10 Enterprise Edition system. There were some problems when preparing for use after the successful installation. After startup, the author kept saying "looking for the local interface", and then the Wireshark software did not respond:

The reason why Wireshark has been looking for interfaces is that Wireshark uses WinPcap as the interface, and the WinPcap included in the "Wireshark-win64-2.6.1" installation package does not support Windows10 systems, so you must first close the Wireshark software and uninstall WinPcap (turn off Wireshark and uninstall the WinPcap installed with the installation package before installing Win10Pcap, otherwise an error will be reported during the installation or the installation progress will not be completed) Then install Win10Pcap (official download address: Win10Pcap official website download), and then restart the Wireshark software can be used normally. WinPcap (official download address: WinPcap official website download) supports Windows NT4/2000 and Windows XP/2003/Vista/2008/Win7/2008R2/Win8 (x86 and x64) systems, while Win10Pcap (WinPcap for Windows10 (NDIS 6.x driver model)) is specifically for Windows10 systems, so be sure to install the corresponding WinPcap (ordinary WinPcap or Win10Pcap) before installing and using Wireshark.

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