My little brothers computer crashes when he plays games. I opened t up and saw that one of the GPU fans (Nvidia GTA 450) stops, and only one of the two keeps running, and it alternates. I searched this up and it said it was a PSU problem, but his PSU maxes at 430W and that is surely enough for what he runs. So I took out his GPU, and inserted mine into his computer (Nvidia 650 TI) and he played games for almost two hours with no problems, where it crashes within a few minutes on his GPU. So I inserted his GPU into my computer, and ran Far Cry 4 and Team Fortress 2 whilst watching videos on youtube, and encountered no problems. I then swapped the GPU's back, and his computer crashes again. No blue screen, just a straight restart. I also think the fans stop spinning have to do with its heating, and is natural for that to happen, as it also did the same in my computer and had no problems. It has been working fine for about 3 months now, and all of a sudden this started happening... I built the computer from scratch for him buying seperate components. He has 8gb kingston ram x1, a F2A78M-HD2 motherboard, and a CPU that clocks at 3.4GHZ, and is dual core. I thought this would surely be enough to at least run browser games, as he also runs those and they crash within ten minutes. I also felt his GPU and it didn't seem very hot at all..