I got a laptop that was infected with newdotnet and webhancer.
I needed to take it back to the office, in order to properly update AVGAS (customer was using a slow telstra wireless card)
Ok, remove using AVGAS, do a disk defrag, remove temp files.
Then I decide to do a MS update, but at some point, I get “files required to use microsoft update are no longer registered or installed on your computer”. I then get a choice to repair… but then the update does some work, then loops back to the error message again…
After the 3rd loop, I find a nice solution at: http://www.petri.co.il/forums/showthread.php?t=4502
Start -> run -> cmd
after typing those commands, everything worked perfectly