We've just had an issue at one of our non-mmanaged clients where they have had a number of machines running at 100% CPU due to the Windows Update Service going bonkers. The solution we have used on all machines is as follows: On the machine in question carry out the following: Log in as administrator. Download updates from step 1 and 2 from KB927891 into C:\ http://support.microsoft.com/kb/927891 Go to Start>Run, type net stop wuauserv. Kill the process ‘svchost.exe’ using 100% CPU if service fails to stop. ------------------- Install updates ------------------- Reinstall WUA 3.0 with option /WUFORCE from step 2. Install update 927891 from step 1. ----------------------- Re-register DLLs ----------------------- Open Notepad and copy/paste the following text: regsvr32 wuapi.dll regsvr32 wuaueng.dll regsvr32 atl.dll regsvr32 wucltui.dll regsvr32 wups.dll regsvr32 wuaueng1.dll regsvr32 wucltui.dll regsvr32 wups.dll regsvr32 wuweb.dll regsvr32 wups2.dll regsvr32 msxml.dll regsvr32 msxml3.dll regsvr32 msxml2...