Firefox recently conducted an automatic update on my computer and
restarted. During the restart process this message appeared:

"One or more files could not be updated. Please make sure all other
applications are closed and that you have permission to modify files
and then restart Firefox to try again."

When I click OK it simply recycles this process and I'm trapped in
this circle.

I have checked my user settings and I'm set as an administrator (using
Windows XP) and there are not other users with anything running.

Any suggestions?