I'm having the same problem on a couple of XPsp2 Machines... one
running IE6 and two running IE7...

All three machines are running Outlook 2007 and Office 2003 sp3...

The Outlook GUI will close, but if you wait 30 seconds... 5 minutes...
two hours... overnight... and double click the Outlook / Email icon to
start Outlook back up again... it won't start...

A quick look at the Task Manager shows that OUTLOOK.EXE never shut
down to begin with ... and now is left in some kind of Limbo State.

No idea what's going on here...

I've run Outlook in Logging mode, but don't seem to see any errors.
The Event Log doesn't show any issues either.

Virus Scanner Norton AntiVirus (Corporate Edition) is running on all
13 machines... but only these 3 (of 5 total in the local office) are
having the issue.