Windows 7 + Counter-strike 1.6

I have counter-strike 1.6 and i want to play it in 640x480 resolution on windows 7 x32. When I set up that resolution i got two big black stripes from the sides.My graphic card is ATI mobility Radeon HD 3450. and monitor 15.4" Diagonal WXGA HD Widescree n display. All worked fine on windows vista, before i upgraded it to windows 7. How i can fix that problem ?? Anyone please help me, I tried to fix this problem for weeks.

Thomas.

Are you sure you could use that resolution with no problems on Vista?
You're trying to use a 4:3 resolution on a 16:9 monitor, so the black stripes are normal. Try to use a Widescreen resolution.