CPU Utilization

On my Windows 2000 Server and on my Windows XP client computer I see a high CPU utilization. Sometimes as high as 100%. I also see a CMD.EXE process running. If I kill that process the CPU sometimes comes down to about 50% plus or minus.

This happens after a hard reboot and after it has been running for a while.

When I look at the processes in Task Manager, nothing is using any CPU. The System Idle Process is typically at 97-99.

However, my CPU is sluggish and the utilization in the performance tab still shows near 100% until I kill the CMD.EXE process.

I have scanned for viruses with E-Trust (Computer Associates) anti-virus with up-to-date signatures.

I have Defraged the computers.

Any ideas of what could be causing my excess utilization?

thanks
doug