External HDD not recognized: Any ideas?

Hey y'all, from the Scorching South!

I have a Maxtor DiamondMax 6B080P0 80G HDD which I am trying to use in a Moving Star External Drive enclosure.

My Dell laptop running WinXP SP2 does not see it. It does not show up in DevMgr, and shows up as "unrecognized device" when plugged in to an old USB 1.0 slot, saying "click here to fix". Do so, and it says "unrecognized USB device." :confused

I also have a 4-slot USB 2.0 Card plugged into my PCMCIA slot, and it doesn't show up at all when plugged in there. Card works great with flash drives, External DVD Burner.

I'm not sure if this issue is with WinXP SP2, a USB issue, or what "link" in the "chain" is the weak one.

Here's what I've done so far: Plugged the HDD into another laptop (Win2k) to see if it'd work. Not automatically! In DevMgr, I see " Maxtor 6 B080P0 USB Device", says it's working properly but does not show under Win Explorer.

I also have moved the HDD jumper to Master, Slave, and "Open", but no joy.

Any ideas, anyone? Even where to start/continue the process of elimination?
All help is hugely appreciated!

TIA,
Figg