OK, I have been working on this computer for over a week now, it sometimes turn on, but sometimes don't. It has my mind boggled.
I'm convinced at this moment that the power supply is corrupt, but I want the root cause of this problem before buying a new PSU. Saying "power supply is the problem" is too broad, it would be very helpful to find out why the computer turns on properly sometimes, but then it turns on with no display at other times.
I have turned the computer on and off over hundred times now, to try to find some common denominator, but haven't been able to find anything.
It just randomly decides to work when booted, but next boot it might or might not work.
I have noticed one thing, turning off the computer, it doesn't shut down fully, the mouse light is still on. That could be the problem, but why?
The PSU has a on and off switch, when I shut down the computer, the mouse light is still on, but when I turn off PSU switch, then the mouse light goes away. That means the PSU is still supplying some power to the computer for some reason.
What could that reason be? Could it be the 4 pin connector problem? I have read that the 4 pin connector can get damaged, and if replaced that would fix the problem. Is there anyway to test the 4 pin connector?
Is it possible to cut the wires from connector and replace it from another spare PSUs I have? That won't do any damage right?