Slightly off topics but!
If you are experiencing svchost.exe hogging 99% of your CPU. Especially at bootup time it is most likely a result of Automatic Updates. This is an ongoing issue with MS that as of yet does not have a permanent fix.
One temporary fix is this:
go to Control Panel, Services, Stop the Automatic Update Service.
go to c:\windows.
Delete the folder SoftwareDistribution
go back to Control Panel, Services and start the Automatic Update service.
This helps stop this from happening but there is not guarantee it will not return some time in the future. If it does then repeat the above procedure.
Also, make sure your anti-virus software is not scanning this folder. Automatic Updates reads the files in this folder every time it checks for updates, having your anti-virus actively scan this folder will only eat up more processor time during an already processor intensive operation.