Clear environment variables of the XP System

Recently, a friend of the author's computer experienced a strange phenomenon: running all commands in command line mode of Windows XP prompts that the command is not an internal or external command, you cannot run executable files or batch files.

Solution:

I believe that the executable files that execute these commands are deleted by mistake. I found that the executable files such as ipconfig still exist in the System32 directory of the system installation directory, there are no signs of deletion or modification.

Step 1: directly running these executable files in the directory can call up a command execution window, but it will flash away. It can be concluded that these executable files are not faulty and are intact.

Step 1: Enter the "cmd" command to enter the command line mode, and then enter the "C: windowssystem32" directory to run the ipconfig command. All the information, such as IP address and DNS, is displayed.

Step 4: click the "environment variables" button in the "My Computer → properties → advanced" tab to view related information. It is found that the path item value in "system variables" is null, which should be the key to the problem. Because the default path is empty, the command system running ipconfig in any path will not be able to find thisProgram. Double-click the path parameter to set the variable value "C: windowssystem32 ".

Step 6: Confirm and enter "ipconfig" in command line mode to display the correct information.

TIPS: If you want to set multiple default paths, use the format C: windowssystem32; C: windows, that is, separate them.

Thinking:

The reason for local failure is that the default path in the environment variable is deleted. Once the default path is set, some DLL or EXE files are required for the current system to run the program, and the active control will be searched in all the default paths. If the corresponding program is found in these directories, it will be automatically loaded. If the corresponding program is not found, an error message for the specified file will be reported.

TIPS: what are environment variables? Environment variables generally refer to the parameters used in the operating system to specify the operating system environment, such as the Temporary Folder location and system folder location. This is a bit similar to the default path in the DOS period. When you run some program sequences, in addition to searching in the current folder, you will also find them in the Set default path. Simply put, the "path" is a variable, which stores the directory paths of some common commands.

Many friends will install dual systems on their computers, such as Windows 98 on drive C and Windows XP on drive D. However, some software is often installed only on Windows 98, but Windows XP cannot be used normally. The more troublesome but effective method is to install it again. When we understand the use of environment variables, we can solve the problem of software sharing in dual systems.

TIPS: Why does the software installed in Windows 98 fail to run in Windows XP (except for green software )? The reason is that when installing software, you often need to copy some files to the system directory, and when using another system, these files cannot be run due to the lack of such files. Therefore, we can solve this problem by setting environment variables.

Example: You can set the default path to solve the problem of dual-system shared application software.

Task Description:

Dual-system local computer is installed, C is Windows 98, Cool 3D is installed, and D is Windows XP. We hope that Cool 3D programs can be normally run in the D Drive System without re-installing the software.

Find the installation directory of Cool 3D in Windows XP and run its execution file. An error dialog box is displayed.

Implementation Method:

Step 1: in Windows XP, right-click "my computer" and choose "properties ". In the system Properties window, select the "advanced" tab and click "environment variables.

Step 2: Add the following directory to the path value of the system variable in the environment variable settings window: "C: windowssystem32; C: Windowssystem; C: Windows" (without quotation marks ).

Step 3: After the settings are complete, you can run Cool 3D smoothly. If you need the system file, it will automatically go to the corresponding directory of drive C Windows 98 mentioned above.

Summary:

Some software can be started normally in the D Drive System without modifying the default path in the environment variables, such as super solution, because they have not copied any files to the system directory. In addition, modifying the default path method is not effective for all software. For some software that requires loading the key value in the registry to be used for startup, a window may prompt you to enter the registration code, after entering the correct value, you can still use it normally. If you still cannot start the software by modifying the default path, it is likely that some DLL files in Windows 98 and Windows XP are different and cannot be used in general, in this case, you can only reinstall the software on Windows XP.