Serial didn't work through emplode either.

Right. It wouldn't. The thing has no disk drives as far as it knows. Watch it boot with hyperterminal, you'll see it searching for disks and never finding them.

BUT, doing an upgrade, did find the unit using COM1. All seemed to be going well (I was trying with 2.0b3 since I can't download 1.03 right now) and the new logo appeared. However, when it got to the "Selecting Pump" portion, no progress ever appeared.

Right, that is expected behavior in your situation. It is able to flash the kernel into RAM, but when it goes to pump the new HARD DISK PARTITION it can't because THERE IS NO DISK.

If there's no magic seal then I'll take a look inside.

Yes, if the seals are on the drive cradle instead of the lid, then you're safe to peek inside. Definitely read through the FAQ on replacing disk drives, though. You have to know how to dismantle the thing without hurting it.

Edit: What am I saying? I'm acting as if the warranty seals have any meaning whatsoever when I'm advising the guy to open his player on a public forum that's read by the very people who do the warranty servicing.

Just peek inside the player and be really careful. It's probably just a loose cable. If not, then call support right away.