ok we know for a fact it is the video card right...... no it cold aslo be other components going bad such as you mother board or even ram..... testing things is the only way.....
we have done this enough to suspect the video card the only way to find out for sur is to pop another card in there to see if it works..... if you cannot do this pop out that card and put it in another pc....
things you could try instead of this before to purchase another card to see if it really is your card is the just reinsert your video card to make sure your connect to the mother board is good. can also try with ram.
if all that fails you could go a cheap route which if it is the graphics card will end up being more expensive. buy another really cheap crappy card just to see if it fixes the problem. or you could buy a really nice fancier card and hope that it's not a component other then the graphics card giving you problems.