After installing the lastest update to my ipod touch I can no longer sync my ipodto my computer no matter what I do. I believe it has to do with the password for my ipod and the possibly the password for my itune account. If anybody has any suggestions

After installing the latest update to itunes, and my ipod, I can no longer sync my computer and my ipod nomatter what I do. I have tried everything I know and can read. I am beginning to think it has something to do with the password that I changed, but I tried to change it back and nothing happens. Does anybody have any suggestions. I have been working on this for three hours and I can't figure it out? Apple is no help and it was their updates that messed the whole thing up.

Kathy295