No need for a cmd. You can change it VIA the registry. That is, if it even exists in your OS.
http://technet.microsoft.com/en-us/library/cc785435(WS.10).aspx

I don't recommend you messing with it though. But if you do, set a restore point just in case something goes wrong.

ASUS M3N72-D
AMD Athlon 64 X2 5600+ Brisbane @ 3GHz
4 Gigs DDR2 PC6400 Dual Ch. Corsair
ASUS GeForce 9800GT 512MB x2 SLI
Win7 64bit or XP Pro x64