I'll through my hat into this ring.
I have the exact same problem as him with a "Microsoft Windows (TM)
Messaging Subsystem Spooler has encountered a problem and must close" with
subsequent loss of e-mail capability and hanging up of Outlook when I try to
close.
Outlook had been working fun with no problems for months/years until a few
days ago. No added programs or configuration changes occured to the system
that I'm aware of.
One other thing, even though Outlook isn't working, Outlook Express is. I'm
able to receive all our e-mail through OE so I know it's not asn ISP problem.
Any advice would be appreciated