iPod Touch 4th Gen Won't Sync...

I have had my iPod for about 1 year, and songs previously have worked & synced before but now they do not.

All my songs got deleted from my iPod and now they wont take from iTunes back too my iPod..

The songs play within iTunes also

And they are all ticked

and i am pretty sure that all the options are ticked too

I think it happened when they changed iTunes over to the new design..But im not 100%..