Cannot install updates - John Aldric

I have a user who I just upgraded to Windows XP Pro from XP Home. For some
reason, it won't install *any* Windows updates. According to Windows Update
history, the last update that was installed was the Microsoft Installer
update last Sunday (August 11th). I upgraded him from home on Friday, so that
was the first update.

I also manually updated him to IE7 to fix a problem he was having with his
internet, and that worked, however, I can't even install the Root
Certificates update.

If anyone has any suggestions, please let me know. I will try to check back
here at least once a day.