I have seen this several times and have one now that will require a complete reinstall. It is not obvious to most people but just makes the machine ultra slow to respond and on low power boxes can make the box freeze for long enough to think the power switch is the only option.
FYI and reference link:
http://www.infoworld.com/t/microsoft-windows/windows-xp-update-locks-machines-svchost-redlined-100-fix-it-kb-2879017-230733#disqus_thread
MS is going to End-OF-Life XP in April but it seems they have started early on the tormenting xp users usually scheduled for that process.
I KNOW some MS workers and managers read this blog and I hope someone is in a position to stop this stupidity.
