ipod nano wont sync to new computer

I've recently changed computers, and found my ipod nano won't sync to the new computer.

I've installed ITunes on the new computer, and manually copied all my songs from my old one to the new one (ie. copied using a memory stick). (I no longer have the old computer so can't use that. Note that I did delete the ipod files from it).

I installed ITunes on the new computer, then added the folders I'd copied my music library to ITunes - so it does see all my music. I've also made some modifications to the library within ITunes - deleted some songs and added some new songs from CDs.

When then I plug the ipod in, ITunes recognizes the ipod is there. I can even open the IPod ie. click 'Devices' in ITunes then the name of my ipod, then under that click on 'music' and it correctly shows me all the songs on the IPod. The problem is that when I click in ITunes to sync the ipod, both ITunes and the IPod display claim to be syncing, but the syncing only lasts a couple of seconds, and no changes are made to the songs on the IPod. The songs I've added are not transferred to the ipod, and the songs I deleted from my ITunes library are not deleted from the IPod.

Does anyone know if there's anything else I have to do. (Before anyone asks, I've done 'check for updates'. I'm running ITunes 10.5.3, and ITunes claims my IPod software is up-to-date - 1.1.3)

Thanks