Yes, it powers on with the red light, but after about 15-30 seconds, it restarts itself without me pressing anything.
I just took it out and put it back in. I just call it "resetting my RAM".
Oh. The more commonly used term is, "re-seating" the RAM. You can actually, "reset" RAM by turning off the PSU via the switch at the rear, and then holding the ON/OFF button in. This bleeds any residual current from the capacitors, and neutralizes any memory cells that might still be biased. (In theory at least. There's a bit of voodoo going on there).
But if the PSU were dead, would it still turn on?
It might. All segments of a PSU do not have to fail at once for it to be bad. There are several voltages, positive and negative, that need to be present, or no "starty".
With that said, I suffered a PF the other night on machines that were in standby. Consequently, I had to do the bleed power thingy I describes above, to get my XP box to boot. Before I cycled the PSU on and off physically, the CPU fan just come on and ran full blast, with no other sign of life from the computer. So, the "soft off" circuit in the PSU wasn't supplying any power to the CPU.
Not saying that's your problem. Just moving the discussion along.
I did a quick read through the whole thread, and it doesn't seem to mention whether or not your CPU fan is starting. Because that's a guaranteed overheat and shutdown in the time period you mention, if the cooler fan isn't running.
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