Outlook 2003 crashes after computer is unlocked

Hey everyone, I have a user whose Outlook 2003 crashes nearly every time he unlocks his computer, and even when his computer is just left alone for a while. Any ideas?

The machine is XP SP2, updated, Office 2003 (Though he had the same problem a while back when he had Office 2002 and Outlook 2003), on a domain.

My associates and I are completely puzzled, any ideas would help.