Problem: SVCHOST.EXE uses 60-100% cpu at bootup or when Microsoft
Update is running.

CAUSE: Bug in Microsoft Update (Microsoft Update scans all Microsoft
software including office/
Windows update only scans Windows for updates)

FIX:
go to windows update and check if the "get microsoft update today"
banner is there, if it is then this is not your problem, if it's not,
click on 'change settings' on the left, in the next window scroll down
and un-tick microsoft update and click on 'apply changes now' , you'll
now be back to windows update only.