windows update broken virtual server on 2003 server?

All our virtual machines open and freeze on the XP loading screen with the
blue progress bar not moving.

I believe this is down to a windows update, as nothing else seems to have
changed.
Has anyone had similar problems?
I removed the following updates, but it still does not work:
KB2158563
KB2259922
KB2347290
KB975558
KB2121546
KB981322
KB982802
KB2141007
KB2124261

The Windows Malicious Software Removal Tool - September 2010 (KB890830)
isn't installed and therefore could not be removed, so I don't know what it
did when it ran...

Copying the vmc and vhd disks onto my machine and running them on virtual pc
works fine.