So he uses Windows 8.1, Eudora, Outlook, and Dropbox.
Yes, I would have gone 0 for 4 on guessing those... And I also would have wanted to know if its the out-of-the-box OS, or if he wipes & uses a vanilla installation.
He might order his Windows laptops directly from Microsoft so the don't contain 3rd party crapware. That should help,security a bit.