Nv4 error

I have a problem with my computer and am at the point that I think the video card is junk, it's a 9800GT, I am wondering if the Nvidea line has the design flaw that the laptops suffered from but, the nv4 driver has a problem and it's consistent, card temps never get above 50, but it will lock up for a few seconds and then the screen comes back with all the colors garbled, am I right or is it a driver issue, using 186.18 drivers