So, after removing my FX5200 for a couple of days and running on a GeForce2 MX, the problems continued. I removed all memory and cards and vacuumed everything. There was quite a build up of fluff around the memory modules. Once that had been removed, I've been stable on the GeForce2 for about a week. I'll be moving back to the FX5200 soon.
Thanks for everybody's help.