" I try to enter a game without letting the machine run for 10 minutes, the video goes into pyscho "
I swap the motherboard in this case. You can research the terms BAD MOTHERBOARD CAPACITORS to see this issue, but the symptom is consistent with bad caps.
I am running with a GeForce Ti-4200 card on a Abit KG7 motherboard. For years, if I try to enter a game without letting the machine run for 10 minutes, the video goes into pyscho colors mode and I have to reset. Temperatures are fine within case and CPU. Suspecting the 300W PSU, I upgraded to a good 400W with no change. Downloaded latest NVidia drivers - no change. I swapped with video card with another (GeForce 256) in another older PC and both PCs work fine. So, I believe I have some quirky compatibility issue between the MB and the Ti4200. I would like to get a 6600GT card but would I be throwing away money since the MB only supports AGP 4X?