How to Fix Windows Update High Processor Usage?
Windows Update can sometimes cause high processor usage (50%-100%).
A possible cause that is worth checking is if you have run low on disk space.
Ensure that there several Gb of free disc space (ie. > 5Gb).
If windows is running as a Virtual Machine, try updating the VM host application,
e.g. check for new version of VirtualBox.
Check out this link, and try running Windows Update troubleshooter, useful link