Hi. Sorry you're having problems with computers. They're a pleasure until they become a pain in the butt. Now, please understand that we are not computer experts at all.
We're just users of Apple equipment. Wondering if there is a licensing problem. When we got our laptop and wanted to download iTunes to it from the main computer (both are Mac) we found out that the ipod can only be synced to one computer, meaning that the other one will not recognize it if plugged in to it. If plugged into the computer that doesn't recognize the iPod, the computer will reformat the iPod and you risk losing the music stored on the iPod.
If we understand the licensing agreement, you can't transfer iTunes from one computer to another, as you must repurchase any music for the new computer. Sorry we don't know how to correct the issues you're having, but hopefully you'll get many more replies. Best wishes.