Hmm... Well, old hardware is always a possability for problems, but, to me, at least, it sounds more software-related.
Do you have a backup you can boot a known-good RTG environment from? ZIP disks are excellent for this. Maybe something you've installed recently replaced some new libraries with older versions? Or maybe some hack or patch didn't agree with a new library or commodity....
Anyhow, I'd try to create yourself a known-good software environment and see if problems persist. Make sure it's not software related before you start messing with hardware.
