hello,
first of all you need to uninstall your current video card drivers and install the latest drivers
download Revo uninstaller from my sig and use it to uninstall your drivers and use it to remove all the registry remaining (it's easy juts follow Revo's instructions) the drivers should appear in the list it's called Nvidia Drivers, just right click on it and choose uninstall be sure to select (advanced)
after you remove them, restart your PC (when first prompted to restart choose no, cause you have to remove the registry remaining, after your remove them be pressing select all and delete, manually restart your PC)
now after that go
here and download the driver, when its done downloading install it
after that restart your PC (yes again :P)
now, there is a very crucial step, you need to update your DirectX
it's not hard at all
just download the latest directX from my signature, when it's done downloading click on it and it'll do the rest, that's it
one more thing
just to be sure that your video card is in an OK condition, let us scan it for any artifacts
download ATITOOL from my signature, install it and open it
now choose "scan for Artifacts" and leave it for about 20 to 30 minutes
if there are any artifacts it should be show as yellow lines and there is a number for artifacts on the bottom of the screen
report back,
good luck