I have had the same thing happen on my Sony Vaio Laptop running Windows XP. It happened about a month ago. I followed this tutorial:

http://www.daniweb.com/techtalkforums/thread82.html

I thought that fixed it for good, but it happened again last night. It's either wmiprvse.exe or svchost.exe that uses 100% of the cpu.
There is also a hotfix from Microsoft that I tried last night. I ran it, then went to sleep... by this morning, my laptop said it needed to update, so I let it... it restarted and then everything worked fine.

The hotfix can be found here:

http://www.microsoft.com/downloads/d...displaylang=en