Are you ready for the day it doesn't start? It sounds just like a machine I worked on last week. It was a real stumper machine but I took a wild guess and cloned the hard disk to a new hard disk. While I was there I swapped the IDE cable and dusted out the machine. That machine is much better now.

The cleaning is very much like you read at http://reviews.cnet.com/4520-11319_7-6240575-1.html
Bob