- iPod touches do not have a disk mode.
- Try a reset:
Reset iPod touch: Hold down the On/Off button and the Home button at the same time for at
least ten seconds, until the Apple logo appears.
- The connect to your computer and try to restore.
- If you can't turn it off, let the battery fully drain. After charging fro at least an hour, repeat the above.
- If you can turn it off, see if placing the iPod in Recovery mode will allow a restore.
- Next if can turn it of try DFU mod.
How to put iPod touch / iPhone into DFU mode « Karthik's scribblings