I was trying to fix something with IE7 and somehow my Outlook Express disappeared. And I couldn't find any of my e-mail files. And then I was freaking out, and running Undelete Programs (which couldn't find my e-mails, either), and realising how much that I needed (including my online plane ticket information) had suddenly disappeared.
And so I gave up and re-installed OE. And there are my e-mails. I have no idea what I just did, but I hereby swear off trying to fix things myself anymore. I'm just glad that all of those e-mails are still there.