My video card speed problem?

How to fix video card problem?

• ok, so my pc broke down a month ago, constantly hanging (may be due to overuse) and so I reformated it. But I as I did so, I found out that my video card overheated and its fan doesn't work anymore.. So I ditched that thing and bought another (second hand Nvidia 7700 GPA) video card,wanting to save some cash. But as it turned out, after a day's use (heck,few hours tops), the display on my monitor became hell. Random color bars pop up here and there, and so I took off the card and plugged the monitor into the VGA display instead. Worked perfectly fine (except,I can't play games or use my image editing software). And so i decided to buy a new card (Nvidia 5500 GPA,that's the only available card at the store near my place) and plugged it in. While the system is loading, the random colors and bars and specks appeared again, but then as the system starts, I was able to use my pc just fine without those nuisance. But after several hours of use, there goes the annoying colors again, and my monitor started blinking to black. So I removed the card once more and plugged my monitor into the VGA. Worked fine after that. So my question is, what is the root of this problem? Is the problem the video card slot on the motherboard itself?

• Answer:

  Since the same problem occurred with two separate cards, I'd say you have a problem with your slot. The motherboard's north bridge is clearly working fine [since your VGA works]. Remove the card, dust your slot thoroughly, then plug it back in. Make sure the card is properly seated. If this doesn't work, test the cards on another machine. If they work properly, you need a new motherboard. Don't worry about the drivers. If your system is Windows XP and above, driver conflicts won't happen - each driver works for its specific piece of hardware.