Files on Desktop - Where are they stored?

I'm looking for some files that were on the desktop that are now gone after I moved my hard drives around. I'm hoping that they're still on the hard drive someplace - I'd appreciate any help.

What happened was: I had a hard drive called "HD A" that had my 10.4.4 PPC system on it. The computer was a 400 MHz Sawtooth G4 tower. I sold the G4 to my daughter. So I installed my store-bought copy of 10.4 on the second hard drive "HD B", then took HD A out of the G4 and put it in a firewire enclosure and hooked it up to my new iMac 17" intel.

The G4 works perfectly using HD B. When I look at HD A (mounted as an external drive) on my iMac, the files that were on the desktop before (that is, when HD A was attached to the G4) aren't there.

I'd like to get these files back. I've tried Spotlight and Find to search for them, but no luck. Are the desktop files stored somewhere on HD A so that I can find them?

Thanks for any help.

G4 Sawtooth Mac OS X (10.4.6)