Compaqs used to have everything custom, virtually nothing generic would
fit, not even memory. Don't know about things since HP got their mitts
on them.

It IS warning you here, swap or fix the PS before you cook something
else. On a lot of cheaply built boxes, the PS fan is the only thing
keeping the MB from cooking itself. If a generic PS will fit, make
sure it has ball-bearing fan(s), more than one would be nice. Most
desktops are built to a price and don't have components to take 24-7
duty. That's part of why server cans are more expensive.

If you're handy with a soldering iron, you could crack the PS can and
swap fans, usually there's some kind of connector to the main PS board
but nothing is standardized. If you're lucky, the replacement fan will
plug right up and work, if not, you get to cut and splice leads. Since
things got hot enough to cook at least once, you're taking a chance
here with just replacing a fan. I've done a lot of this type of
replacement in the past when I could scrounge good surplus fans for
cheap. These days, a fan's going to cost you about a third of what a
cheap supply costs off the shelf, more if it's ball-bearing.
Replacement fans can be had at retail from the likes of Digi-Key and
Mouser. Radio Shack has some types, too, if you just gotta go local,
no pedigree with those and about the same price as the name-brands.

I've had good luck with Antec brand power supplies, Power Supply and
Cooling ones are good, too, just expensive. I think P.S.&C. also offer
some supplies for some of the brands with custom units. You could
contact them for recommendations, anyway, doesn't cost to ask.

Stan