I don't have the lock up problems you describe but I am suddenly having problems with emails. Any emails I send from either Outlook or Windows Mail, people who receive emails from me are shown the MIMI contents of the email, not the rendered version.
I have looked at the raw file that is created in the Outbox folder and it seems that a 'boundary' section is missing from the email. I gather
that when the receiving client receives this faulty structured email it doesn't know what to do with it so just displayes the whole lot.
As I said, never had an issue until yesterday so can't help wondering if something has been changed in the last round of Microsoft updates which happened on 12-12-2008?
I'm waiting til tomorrow to see if my works PC is suffering with the same problem.