I have a roughly two year old Dell which has an NVIDIA GeForce 7900 GS video card in it. I ordered it from the factory with that card specifically. For a long time it just worked and it worked fine. I was able to play World of Warcraft at just under max settings and still get around 60 FPS (not that WoW has really hefty requirements). After some time, however, I began to notice some issues. The first thing I noticed was that on the Windows startup screen (the one with the little scroll bar) I would see what I describe as artifacts. They show up randomly as small squares (pixel size or slightly larger) that are different colors and their position and color are different every time I restart. After a while, while playing WoW, I began noticing that if I turned my character in different ways, I would see random polygons appear out of nowhere, then the UI started getting strange (i.e. certain parts would get distorted, text would become distorted, etc.). Rebooting doesn't seem to fix the problem. I tried upgrading the driver, only to find that the driver that shipped with the computer is some sort of strange dell driver that allows it to display 1600x1050, whereas the newest stock NVIDIA driver apparently doesn't support that resolution (unless you jump through some hoops). I did manage to get the NVIDIA driver to work, only to find that it didn't fix my problems. So now I'm wondering if this is a heat issue. The computer is not in an overly hot place (it's in my room and that's mostly cold). I've removed the card to make sure the heatsink/fan isn't caked with dust and it isn't. Has anyone noticed these issues with any NVIDIA cards? Is this a problem with this card? Is it overly sensitive to heat? Any suggestions would be appreciated. I really don't relish the thought of having to spend $300 on a new card.

Thanks in advance.