Windows 2000 Pro: System process hog!

In installing a Hayes Accura modem into a (currently) dual-booting HP Brio (the OSs are on separate partitions), I switched from win95 to startup win2K (as I have several times over the course of this week), and win2k took over 2 hours to startup!
Consulting the Task Manager revealed that the hog was the System process which was taking up 99% of the CPU!
If anyone has any experience of this, and would care to shed any light on the phenomenon, I would be most grateful!