I was just curious at this point. Did the computer get plugged into the same outlet as the first burned out one? I’ve seen examples of electronics going bad because of bad grounding. Sockets on different circuits having a voltage of 60V between their grounds. Spikes going down powerlines burning out appliances one at a time. Solved the last one by putting a surge protector in the main breaker box. They might want to check out the socket for problems, before they connect another computer.
I don’t think so; there was a lot of dust inside, so I think the life of the thing may have been shortened by borderline overheating.
Thanks for all your help on this one; I really appreciate it.
I was thinking about the possibility of a double failure.
Did you ever try the new CPU on the old Motherboard? If the old processor and the new motherboard are both bad, this should work.
I tried that this morning;
-Old cpu in old MoBo: Power LED only, before even powering up; processor fan twitched once on one occasion
-New CPU in old MoBo: Fans run continuously, even before powering up, but nothing else.
-Old CPU in new MoBo: Nothing at all
-New CPU in new MoBo: Nothing at all.
K, looks like at least 2 failures, maybe 3. I doubt you’ll figure this one out without throwing even more hardware into the mix.
Grasping at straws:
Check that the “clear CMOS” jumper on the new Motherboard is in the correct position. After that, I got nothing.
Yeah, I checked and rechecked jumpers (there aren’t actually all that many of them in total. I only hope that plugging the new CPU into the old MoBo hasn’t knackered it (and if it has, that plugging the now-knackered new CPU into a replacement motherboard won’t kill that, in an infinite regression of turtles).
Well, I sent the motherboard back and received a response saying it had tested faulty (I don’t actually believe they even tested it - they’re a high-volume seller with narrow margins, I suspect this is ‘yeah, whatever’ and that they’ll pass the board back to the manufacturer for credit regardless).
Anyway, the replacement has now arrived and I tested it on the bench with the a minimum of other components; it seems to behave OK, so I’ve fitted it into the case and put everything else back as it was; it still powers up OK… so far, so good.
I know I’m going to have fun and games getting it to boot into Windows with a brand new processor and MoBo. I have to find a spare monitor to hook it up to now…
It’s about time something went right. Good luck.
It boots up OK and passes POST, but Windows isn’t playing ball - it loads a few bits and pieces, then reboots. I’m sure this will be because of the motherboard drivers in the HAL or some such - looks like I’m going to have to reinstall Windows on this machine; I’m not sure what kind of reinstall media will have come with it; I’m betting it will be an image-based restore disk, which isn’t going to help, as it will be trying to restore a system based on the old MoBo…
Just wanted to say that I’ve enjoyed following this thread. 
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Good luck going forward!