Hi Arvind,
I just want to advice you in case you don't know that each program receives
copy of the environment variables upon starting. Thus, changing envirnoment
variables won't affect already running processes.
Even more if you change the environment variable used in the local machine
that changes won't take effect until you log off and log on. The other way
to propagate the changes is to broadcast WM_SETTINGCHANGE message so, the
programs interested in those changes like Windows Explorer for example can
update itself, however boradcasting that message won't update running
processes environment block.
How to change the environment variables look at MSDN
off-line:
ms-help://MS.MSDNQTR.2003FEB.1033/enu_kbwin32sdk/en-us/win32sdk/Q104011.htm
on-line
http://support.microsoft.com/default.aspx?scid=kb;en-us;104011