CT2600 -
Other than hooking up the KVM switch, did you change/add/delete anything else on your system hardware or software - wise? As nihil suggested, I would try reinstalling your RAM one stick at a time . . . taking note of any discrepancies during bootup. Have you checked for driver updates for your AGP card and/or possible conflicts when using a KVM switch??

What does the inside of your system look like? Have you cleaned it lately? Sometimes excess dust can create more problems than you'd think.

V.