Zogo posted:

Try different peripherals. It's rare but even a malfunctioning mouse, keyboard, printer, monitor, speakers, cat5 cable (ANYthing connected) to a computer can cause oddities like this.


Also, use different SATA cables if you haven't already.

Also, try only one stick of RAM.


Worst case scenario is that one of those PSUs has gone bad and is simply frying different components as you switch them out. How old are the PSUs?