Looks like the CompUSA guy's theory was bad. I brought the Mini back this afternoon, just got it set back up, and had an email back from Apple on re-downloading purchased music - and the machine started to get flaky. Menus disappeared, applications misbehaved, and then it wouldn't reboot. Suspiciously like the other day. So, I think the HD is just toast. Back it went, and now I wait for the call from them.

In the meantime, not all was lost - Borders is next door to CompUSA here, so I waled over and got a book that was recommended to me (via email): "TWO QUEENS IN ONE ISLE: The Deadly Relationship of Elizabeth 1 and Mary Queen of Scots"