From time to time, you may get a Windows Update failure. Either the updates don't take as planned or you get stuck on the 'installing x of x' screen and the only solution is to reset the machine. On reboot, updates from that point on (especially if reverting back to changes doesn't work) may seize and corrupt. To correct this, you need to go into the Windows Run area, and type in 'cmd' as an administrator.
You then type 'net stop wuauserv'. This stops the windows update process.
Then type 'net start wuauserv' to restart the updates process.
Hopefully this corrects this updates problems and you can continue with windows updates going forward.