Restore only works on Mac?!

Question

Until last week I had a perfectly happy primary connection (since Nov.) to iTunes on my PC, and had also successfully added songs to the iPod from a first gen iMac (running OS 10) that I also have, with no troubles. I know Apple does not encourage that sort of thing, but I had no trouble at all.
Then somehow while adding songs from the Mac, iTunes "updated" the firmware on the iPod, and the Mac apparently reformatted my iPod without asking. The PC ceased to recognize the iPod, and though I could browse them all, the iPod would skip over all PC-formatted songs I attempted to play until it reached one in Mac-format which it would play.
I thought I'd simply do a restore on the PC and call it a day, but just as the restore began, the process tanked and I got a "firmware error diskwrite error" and the alarmed folder icon on my iPod. I've since learned that I should have been told the iPod was Mac-formatted and asked if I wanted to reformat. I was not. The disk appeared on the updater as "unknown" format.
I CAN and have done a restore on the iMac, always successful, though the updater afterward identifies the iPod's format as "macintosh" (is this the "factory" condition promised?) and the result of an attempted restore on the PC is the same error.
Any thoughts?
Thanks
Ancient Dell Dimension 4100 (866 Meg pentium)   Windows XP   30GB iPod 5th gen
Ancient Dell Dimension 4100 (866 Meg pentium)   Windows XP  

Answer 1

Thanks Jeff-
Windows did see the iPod in disk mode, but attempting to format from there failed and froze the iPod...
I ultimately tried a restore on another PC, which I should have done earlier, and was successful.
Then I discovered the real problem that I'd been missing:
I had been switching USB ports (per apple's instructions), but only between the several offered on my USB 2.0 expansion card (which is all the same faulty COM connection apparently), which continued to crash Windows when I tried to update the iPod from iTunes (it could see it, it just really didn't like talking to it).
Finally, I tried the built-in USB 1.0 port (computer is admittedly ancient), lo and behold, 6 hours later I had 12 gig of music back on my iPod. I am going to reinstall the drivers for the USB 2.0 card and see if that helps, I don't consider USB 1.0 fixed!
iTunes is still giving me a communication error and failure when I try to update photos and contacts, is this symptomatic of the same problem, a different one, or is it just too much data for iTunes to allow over a USB 1.0? The latter would seem odd to me.
Add to this that I recently added Norton Internet Security 2006 to my computer, and even though it appears to be playing nice with the iPod, I can't help but wonder if it's part of the issue.
Any other thoughts would be helpful.
And thanks again.