Is the problem my video card?

I have a question and hope this is the forum to post it in, if not please let me know which one and ill post it there. My computer is used for video games for the most part, well for 99% of it . The other day while playing a game it locked up then crashed. It went thru this 3 or 4 times before I had to go to work. The next day my wife was on the internet sending e-mails and some of her office work without any problems. I then loaded up a game to play online and the samething happened. Then the last time it looked like someone tossed confetti over the screen(Lots of blocked colors) and now I dont get any picture. The computer sounds like it starting and running the same but nothing on the screen. I have a Geforce 6800 card that is 2 years old. Anyone have any ideas on where my problem could be? Video card,motherboard? Thanks for your help

sounds like time for a upgrade

Thanks again for you help, one more question I have a motherboard that only has AGP. Should I upgrade the motherboard/cpu to get PCIe slots for the videocard. If so can anyone suggest a good motherboard/cpu with video games in mind?