You should just need to update the video card drivers, but if you have not done that, then you probably need to look into updating several things.
Video Card
1) Go to
http://www.nvidia.com and download the latest driver for your video card. Be sure to save the file on your hard drive and not to your desktop.
2) After the download is complete, note the location of the file as you will need it later. Shut down any and all programs and get to the Windows desktop.
3) Press the "Start" button on the taskbar.
4) Select the "Settings" option.
5) Go to the "Control Panel".
6) Open the "Add/Remove Programs" ICON.
7) Find the "NVidia Display Driver" in the list. NOTE: It could be named something else, based on the actual model/brand of card you have.
8) Remove the driver and Windows will want to reboot. Do so.
9) During the reboot, Windows will detect the video card driver and try to load the driver again. Make sure to cancel this opertion. Do not let Windows re-install the driver.
10) Now you should be in VGA mode, which makes the screen look a bit ugly.
11) Find the file you downloaded from NVidia's WEB site and exectute it (double-click).
Answer the questions, reboot when prompted, and you are done.
It is not a daunting procedure, but it does require a methodical approach.