well, once you got it to win format, you should of left it there, it would of worked on the mac with no problem. but the main thing is you formatted it with the disk utility, which is what killed it as an ipod. the disk has to formatted a special way for it to be seen as an ipod by the computer, and not just a hard drive. but with the issues it had before, i'm inclined to think that either the hard drive is going, or the hard drive controller and/or computer interface is bad, which means the ipod is no more.
Digital Audio G4/1.467ghz, 1.5gig ram, 16x Superdrive, 256mb DDR3 AGP 6800GS, zip, 2x500gig raid0 for 1tb on sonnet tempo trio, 10.5.4