4th generation iPod NOT syncing?

I think it's the 4th, its the one before the video one. Well every time I try to put this one movie on, it says that there's an error and it cannot sync because it can't find the disk. I read up on it and everyone thinks it's a USB issue or a mouse problem. I use a laptop WITHOUT a mouse and switched it to every USB port on it. Still the same error. Itunes is up to date and everything is authorized. Oh and the iPod doesn't show up in the my computer folder either. So I can't drag and drop the movie there. Soo....what else can I do?