> cpu usage will go to 100%

Yes, I've had problems such as this before. However, I was never able to pin down the cause. I did notice that whenever I logged in as myself I would get this problem, but if I logged in as someone else the problem never showed up.

The only thing I was able to determine was perhaps my NT user profile was bloated. Since then I have migrated to W2000 with no problems.

Good luck!