Changing System Environment Variables

On Win2K/XP, environment variables are contained in the Registry.  System

wide variables are contained in

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session

Manager\Environment.  Per user variables are contained in

HKEY_CURRENT_USER\Environment.  If you change any of these values, you should

also broadcast a WM_SETTINGCHANGE message to alert programs to the change.

On Win9x/ME, environment variables are read from Autoexec.bat and can't

easily be changed without rebooting.  There is a program call WinSet which is

on the Win9x CD-ROM which will change the in memory image on the fly.