While someone else was playing on a PC at home, the computer just suddenly turned off and he couldn't turn back on. He asked me to check it out.
The house power was fine.
The ON button indeed doesn't work.
Then I smelt something burning, which came from the PC.
Sniffing carefully, the smell was strongest coming from some ventilation holes in the PSU. Now, to support this, the 550W PSU appears to be dust filled, quite hot even after a few minutes, and was a really cheap crappy one that came with the case. Yet the PC was only on for half an hour or so during this day.
But the only thing holding me back about blaming the PSU is the computer is still partially powered. The computer is off, and the motherboard LED indicator is still lit.
Also, I turned off the PSU and wait for the power to drain from the motherboard, and after a while, I turned it back on. Right? Now I hit the ON button. The computer doesn't turn on, but I notice the fans move slightly, as if there was a trickle of power that actually came through. The fans only move once after each time I reset the PSU.
All other components of the computer seem fine. The only things that are powered while the computer is off is the motherboard, the USB keyboard, and USB mouse. Yet it cannot power up the computer.
I don't have a proper voltmeter to test out the PSU. I don't want to waste my money on a new PSU for nothing, if it was another part of the computer. You guys still think it's the PSU that's at fault?