Windows Logoff...

I want to be able to track when a user is logging off windows. I only need to track this when they use the log off(not the restart, or shutdown). I assume this can be done with the query_unload event of a form, but I am not sure how to distinguish between a restart, shutdown, and logoff. Lastly, and perhaps most importantly, it should only log it if the machine is being logged off. To clarify, some programs are capable of prohibiting you or prompting you before it actually logs off. If I were to log it, then a program were to prohibit from logging off, my program would be shut down and would have improperly logged the information. How do I insure my program only logs when a logoff is successful and is not prohibited? Thank you for any help you can give.

Joe