I came home from travelling this week to find one of my two desktop PCs dead. It's about 4 years old and was a home-build Athlon 64 machine. I'll call it Computer A. The problem? Power switch did nothing. Opened the case, internal mobo LED illuminated. Strange. Switched the PSU off and on again, CPU fan twitched slightly (normal), LED illuminated again. But utter silence when I press power. Headers connected correctly - check. Tried switching power/reset button connectors to make sure. Nothing.
So I assumed that the motherboard had some kind of problem, but had no idea how to test the theory. I left it and fired up Computer B, an ageing Athlon homebuild from about 8 years ago which still works well. It transpired that one of the two HDDs was on it's way out, so I backed up everything to an external HDD and set about removing the dying drive. My plan was to switch the second drive to be the master and do a fresh install of XP on it.
At the same time I decided (error?) to transplant the internals of this computer (Computer B) into the now vacant case of Computer A, as it was smaller and lighter. I did so, connected everything up, switched on the PSU - mobo LED illuminated - and hit the power button. Nothing.
I reasoned that maybe somehow both the power and reset buttons of Computer A's case had crapped out simultaneously, so I hauled everything back to the old case. Now Computer B, previously working fine except for the temperamental HDD, was exactly as it previously was, minus the dodgy drive. Connected everything up, hit power, nothing. Dead.
Now, given my zero knowledge of electrical engineering, and the sequence of events that occurred, the only possibility I can think of is this. Computer A's PSU went bonkers one day for reasons unknown and fried something on the motherboard. The LED comes on but all else is quiet. I've just put Computer B's mobo in the same case with the same PSU and fried that as well. I can't think of any other reason why both PCs are now corpsed. Of course, this being computer hardware, about a million other things might have happened which I don't, can't and won't know about.
So if anyone has any advice, possible ways to isolate the problem or to prove or disprove the fault of the PSU and motherboards, or anything else that might somehow rejuvinate at least one of my desktop PCs, I would very much appreciate it.