The way that I solved this problem was to plug in an old keyboard with the round connector. Unfortunately, I don't have a similar mouse, so I had to use the keyboard to navigate through windows. Vista creates an automatic restore point before it installs any updates, so you should be able to go to Control Panel -> Backup and Restore Center -> click on (sorry, I mean tab to) "Use system Restore to fix problems and undo changes to windows" -> tab down to the second option "Choose a different restore point" (use spacebar to change the option and press enter). Select the restore point before the update (released on 14 Nov 2007).
Next -> Finish -> Sorted.
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