My uncle was cleaning out his computer and removed the processor fan and the graphics cards to hoover out the fans. His machine then wouldn't work. After looking around I found out that the CPU had been stuck to the heatsink and when the heatsink was put back in it hadn't put the CPU right in the hole and the pins had bent.
After replacing the CPU the machine still wouldn't start up. After trying a different power supply and a different graphics card, and with no hardware except the CPU and 1 stick of memory it still wouldn't work. I decided to replace the motherboard with a second hand one that was confirmed working. I plugged it all in and it started. We left it for a few hours and it seemed fine. Then it cut out and now won't turn on.
After looking inside again it seems the processor and the CPU-FAN header aren't working, despite the 4 pin plug in perfectly and I've tried with another PSU, however the fan works fine in the SYSFAN header.
After all this, my question is, is it possible that the PSU has fried 2 motherboards? And is it worth getting another motherboard with a new power supply?