If i understand, your ipod is not detected by your system?
After plugging the ipod in the device. Go to device manager (In run type "devmgmt.msc") In Device manager go to "Universal serial bus controllers" It should list the storage devices that you have connected to your PC. Right click and then click "Uninstall. Remove the USB drive and restart your system.
Try connecting the ipod again, i think this should solve the problem.