Just like in Windows NT 4.0 and Windows 2000, environment variables are strings that contain information about the system and currently logged on user. To manage System variables, you must be logged on as a member of the Administrators group.
If you open a CMD prompt and type SET, you will receive a list of many of the users and system variables. The System variables that you can manage are stored in registry at the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment key.
To manage environment variables:
1. Right-click My Computer and press Properties.
2. On the Advanced tab, press Environment Variables.
3. Select one of the following options, in either the <UserName> or System area:
- Press New to add a new variable name and value.
- Select an existing variable name and press Edit to change its' name or value.
- Select an existing variable name and press Delete to remove the variable name.
NOTE: If you change a System environment variable, you may need to restart your computer.
NOTE: If you change a user environment variable, restart any open application, or log off and log on.