After repairing the power supply the other day, all seemed to be going well.
This and other servers I control run MySQL for various purposes, and like the good administrator I am, I regularly store back-ups for disaster recovery.
My current gig isn't very busy, again, and I've been given too much free time to think of other things to do.
MySQL has just released version 5 of their database engine.
This is currently being served by the 64-bit MySQL 4.1.13 installation on the server! Woo and hoo!
So after a few hours sitting at the terminal of the server, I found that the problem wasn't with MySQL after all.