Whenever posting questions on these forums, please give us as much information as possible about your computer. Depending on your issue, we might need the operating system, processor speed, amount of RAM installed, brand name of the computer, (if there is one), and any EXACT error messages you are receiving, plus anything else you think might be helpful. The more information you give us, the better informed our answer will be.

In the meantime, have you tried visiting your video card manufacturer's website and installing the most recent drivers for your card?

Hope this helps and let us know more.