Be sure the nVidia is the only card being used. You want to disable any on-board graphics.
How to determine your nVidia driver version
Right click in any open area of the Windows desktop
Select NVIDIA Control Panel from the popup window
Select SYSTEM INFORMATION at the lower left corner
Driver version should be the 1st line in Details
I have a GTX285 using driver 296.10 and Win7
What is your driver version number?
You also need 1Gb of RAM on the video card minimum.
That only applies to hardware acceleration. It's not a factor with the card simply working to drive the display.