Outlook 2007 won't exit

[Steve]

I have a weird fault on several of my users email accounts. We are using
Exchange 2003 SP2. When they open up Outlook 2007 (with SP1), it crashes
straight away and has that box ticked to say "restart outlook" and when you
click ok, it just crashes again and again, etc and etc.

I discovered that this fault was related to having Windows Desktop Search
3.01 installed and having removed WDS the accounts no longer crash on open,
however when I go to try and close Outlook it will not exit (either by
clicking the X or File, Exit).

I suspect it is some plug-in failing but if I go to the Trust Centre,
Outlook will freeze and I have to go to Task Manager and Force Quit it.

Can I run the Trust Centre independent of Outlook so I can see what might be
causing this problem? Or does someone else have some other solution I could
try?

Thanks in advance,
Steve.