A combination of problems...help!

My 30 GB iPod video does not play some of my movies. it has played them before without problems but suddenly i clicked one, the screen went black for a minute, and then went back to the movie menu. Also, my iPod is recognized by my computer, but not by iTunes. I tried to restore, but the newest iPod updater will not even update my iPod. I have reset the ipod many times, reinstalled itunes...etc. Anyone an ipod wiz that has any clue what to do?

Windows XP 30 GB White Video iPod