I built a computer for a friend about 3 years ago. A few days ago the computer crashed to bluescreen and then shut down. When booting the next time, there were artefacts all over the screen. The computer would boot into Windows and then crash again after about 30 seconds. This was an obvious graphics card issue I thought, so we got a new card (GTX 660) and popped it in.
Everything was looking good, the computer booted into Windows, but it still shuts down after about 30 seconds. No bluescreen, beeps, artefacts, or diagnostics information at all, just a shutdown. This made me believe that the PSU (Corsair 520w) couldn't handle the graphics card. The recommended wattage for this GTX 660 is 450w.
We ended up buying a new PSU (Corsair 600w bronze certified). This PSU should handle a system with a GTX 660, a Intel Quad 6600, one optical drive, one hard drive easily. Yet we get the exact same shutdown after about 30 seconds in Windows.
I have tried booting into safe-mode to remove old graphics drivers with Driver Sweeper, but it still shuts down after a while. So I don't think the drivers are the problem.
This is driving me nuts. The next component to switch could be the motherboard, and that means we might aswell get a new CPU when all we wanted was to replace a faulty graphics card. I don't know what else to check. Since I can't find any diagnostics information, it just feels like fumbling in the dark. Any ideas?