I recently had a bad case of boredom. I had a friend's Dell B110 that had a hijacking problem.
Going through the system was a pain. P4 processors are just too slow!
I had just upgraded my wife's HP, with a new board processor, RAM, and PSU. So I had a bunch of good, older, quad core-based stuff just sitting around.
I checked out the board on the Dell. It was a mini ATX. So was the wife's. I checked the mounting points and they lined up.
So a half hour and a phone call later, I had permission for a change.
The Dell board had Realtek AC'97 audio, the HP Hi-Def. So the front audio connections don't line up. Everything else did.
The green Dell fan duct fit over the heatsink fan on the AMD Phenom X4 9650 Agena 2.3GHz that was on the ASUS M2N68-LA board.
I had a problem with the CPU fan. It somehow died. Once it was replaced, no problems.
That old Dell, now runs Win 7, has 4 GB of GSKILL DDR2 667 (PC2 5300), has Hi-Def audio, has a DVD R/W, instead of a CD player,and will run circles around any old Dell.
I could have bought a new case and new HDD, but my friend really didn't need them. This was just a low budget, "can I do it?"
Just a little post to give ya some ideas on what to do with them older parts.