Can;t manually sync music

I have recently updated to windows 7 64 bit and installed the new itunes etc. I have tried to back up my phone and this did work and I thought I would try to not sync as I would loose all my apps but I would just drag and drop the music I want accross. I tried to transfer pruchases but each time I try itunes keeps stalling. Then to my shock I find that I have no content in my ipod (songs all gone), however on the bar accross the bottom of itunes on the pc it says I have 3GB of audio content. I have tried to drag and drop songs, it does it all etc then I check the phone and no content in the ipod music section.

I am sturggling really, do I just need to go for a sync and hope for the best my music comes back or i'll then be able to drag and drop the music over or is there something I am missing? Itunes is authorised with this comput and I have got all my songs on my pc neatly sorted in my itunes.

Please help, this is very frustrating.

The other point is that it keep telling me I need to update my phones OS to the latest4.3.1 which I havnt done yet for fear that itunes will stall half way through as it seems to do a lot and I have to force close it and start again.

Can anyone help please.

Thanks very much

Mr_Wal