About two years ago I had my friend build me a computer and it was really good. I had no problems with it at all. Until a couple of months ago I started noticing what I now know to be artifacting. I asked my friend what he thought it was and he explained that it was the video card. So we take it out clean up my computer (dust etc.) and notice a thick film of dust coating the video card. We take out this dust and try it out on his computer. It still artifacted. He tried to see whether or not the fan was working or if it was overheating. The fan worked properly. Then when I put it back in my PC, it started bugging out and restarting and random times of usage. Sometimes it restarted upon booting into windows, sometimes after regular browsing, sometimes during a youtube video. Just anytime. Then me and him swapped video cards and it ran smooth for a couple of hours, until in the middle of testing out Oblivion, the game just started terminating and going right back to windows, and other times, the computer restarts. I have no friggin clue what to do, seeing as I really don't want to waste and unnecessary money. If anyone can help, I'd really appreciate it.