I have now experienced this problem on a few occasions and it has now irritated me to no end.
When opening Outlook (used vesions 2003 and 2002) it takes forever to open and is very unresponsive when it finally does. I check in the Task manager at the processes and found that msgeng.exe is using up all the system resorces. When I END the process the machine is back to normal.
This has now happened on various machines.
I recently installed XP from scratch on my Notebook, but the problem has re-emerged!!!