Hi EdieinDeep, Welcome to Windowsbbs!
The Windows Management Instrumentation Service runs under one of the svchost processes along with a bunch of other Windows Services. Are you sure that there are no other processes that are causing the CPU
usage to spike to 100%?
Download and run Process Explorer
and see if you can identify if there are other Windows Services or processes that are causing your CPU
usage to spike.
Also one other thing you can try it is to Perform a clean boot to troubleshoot a problem in Windows 8, Windows 7, or Windows Vista
and see if you can rule out other 3rd party programs causing a problem.
Having the WMI service using 60%-100% of the CPU
is not normal and that behavior definitely should not be happening.