If you hold the play and menu button down at the same time, it will reset. It will also do this if you do not use it for 24 hrs or so. You can also right click or option click the iPod in iTunes and set the disk mode.
That didn't work it is realy odd. When i plug it in with FireWire its says "Disk Mode OK to disconnect" with a check mark on tyhe screen. But when i plug it in with USB is says " Do not Disconnect" until it runs out pf batterys