Windows NT requires certain information to find programs, to allocate memory space for some programs to run, and to control various programs. This information — called the system and user environment variables — can be viewed using the System option in Control Panel in the Environment Variables tab. These environment variables are similar to those that can be set in the MS-DOS operating system, such as PATH and TEMP.
The system environment variables are defined by Windows NT Workstation and Windows NT Server and are the same no matter who is logged on at the computer. If you are logged on as a member of the Administrators group, you can add new variables or change the values.
The user environment variables can be different for each user of a particular computer. They include any environment variables you want to define or variables defined by your applications, such as the path where application files are located.
After you change any environment variables in the Environment Variables tab in the System Properties dialog box and click OK, Windows NT saves the new values in the registry so they are available automatically the next time you start your computer.
If any conflict exists between environment variables, Windows NT Workstation and Windows NT Server resolve the conflict in this way:
Note
Path settings, unlike other environmental variables, are cumulative. The full path (what you see when you type path at the command prompt) is created by appending the path contained in Autoexec.bat to the paths defined in the System option in Control Panel.