http://www.apple.com/support/ipod/five_rs/
2. Try to put the iPod into Disk Mode if it fails to appear on the desktop
http://docs.info.apple.com/article.html?artnum=93651
Still can't see your iPod?
Several things could keep iPod from appearing in iTunes or in the Desktop/Finder when you connect it to your PC/Mac. The most likely causes are listed below in logical order. Check each one starting from the top of the list to see if that is what's keeping iPod from appearing.
3. Try to wait 30 minutes while iPod is charging.
4. Try another known-good FireWire or USB through Dock Connector cable.
5. Try another known-good FireWire or USB port on your computer .
6. Try to disconnect all devices from your computer's FireWire and USB ports.
7. Windows users having trouble with their iPods should locate a Mac user. We've found that in many cases when an iPod won't show up on a PC that it will show up on the Mac. Then it can be restored. When the PC user returns to his computer the iPod will be recognized by the PC, reformatted for the PC, and usable again. BTW, it works in reverse too. A Mac user often can get his iPod back by connecting it to a PC and restoring it.
8. Try to do a Erase (Disk Utility) on a Mac computer or a reformat with a PC (Disk Management tool) but ensure you choose the right Drive (your iPod not your Hard Disk of your computer).
9. Try to run the iPod in “Diagnostic mode” . which can be accessed by pushing the “hold” switch into the “on” position and then “off” (into the original position). Then press the following buttons in the following order: “menu” plus “select” (centre button) then press “reverse” plus “select”. This will take you to the hidden diagnostic mode screen menu. It may take a few trials and pressing the buttons in the right way for this to work, so be patient and keep trying if you have to. The diagnostic mode will give you 7 choices which are: Memory, IO, Power, Status, SysCfg, Diskmode, and Reset. Don’t bother trying “reset” because in my case it didn’t work it just took me back to the same problem. Instead, choose “diskmode”, after which you should get an odd looking “ok to disconnect” sign on the iPod screen.
If one of the above step helps to get your iPod to be recognized with your computer, do a Restore.
But, if none of these steps address the issue, your iPod may need to be repaired. You can arrange for service at the iPod Service Website.