I have a 6-year old P2-400MHz. All it needed was a new HD (which it needed anyway, because 8GB isn't as impressive as it used to be) and a new fan.
Dumb question.... what would one do with such a system? I'm not joking, I'm curious.
It's actually quite useful. Besides this old P2-400MHz machine, I have a desktop, two laptops, a TiVo, and a Sony PS2 (but the PS2 doesn't really fit in here).
On this old P2-400MHz machine, I installed Linux, and it is the 24x7 server for my home network:
- Home Media Option server for TiVo (photos on my TV and MP3s on my stereo system).
- DHCP server for the other computers.
- DNS server for the other computers (internally, so they can find each other).
- Squid web proxy cache for other computers.
- Backup server for the other computers.
None of it is performance-intensive stuff, so 400MHz is just fine. All in all, not bad for a machine about to be thrown out of the office