High CPU Utilization

[Bill J]

I have very high CPU utilization on a regular basis with
no obvious applications running. When I look at the Task
Manger under processess, the most active user of CPU is a
task called System Idle Process. It is running the CPU up
to 60% constantly. Obviously the rest of my PC
performance is being affectd. I have 512 RAM running an
older PII-400. This is relatively new issue, with the
past 3 weeks. How can I find out why this process is
running and hopefully kill or stop job?

Thanks!