Hi Paul:
I Googled "svchost.exe" and got LEO, the IT guru's column on this very topic. If true, then it may either be a virus, an exploit, or worse. He runs you through what to do here-
http://ask-leo.com/svchost_and_svchostexe_crashs_cpu_maximization_viruses_exploits_and_more.html. Several other sites discuss fixes, including downloads of applets which can help you fix the problem. Leo's article, though, even includes multiple links and information sources... good stuff.
Good luck! Let us know how you fix the thing...
