Strange daily Outlook occurence

I have a user that sent this to me in an e-mail last night. I read it and don't have a clue so I thought I'd pick your brain and see if you have any thoughts on this. We use Windows XP sp2, Outlook 2003 and Exchange 2003. Everything is on the latest service packs.

"For about the last two weeks or so, when I open my computer in the morning upon arrival (it is always on, so I just turn on the display), I find a blank e-mail in my Inbox, as if it were a draft. The heading above the address section says "This message has not been sent." Yet it is in my Inbox. It is always time stamped between 9:04 and 9:08 pm. There is no content, and I have simply been deleting it everyday."

Does it happen if you disconnect the network overnight?

I don't know. I had him shut off his pc last night, since it is always on, and it didn't happen this morning. Any thoughts on that?

Hmmm... Was trying to determine if the email was being created by 'outside influences' via the internet, or, will the computer itself create the email even without the internet?