Ipod 160g music library shows up when connected to itunes, but empty when disconntected from computer

Question

At some point last night the mac i had connected to my ipod 160gb went to sleep and when it awakened, I ejected and disconnected ipod, instead of going right to the music menus, the ipod restarted, and opens up the language selection screen, as if it is empty.  There are 0 music files, 0 videos, playlists etc., actually it even says 0 KB available.
When i reconnect to my computer i have access to my ipod library on my ipod like normal.
I have tried doing the hold switch toggle and then holding menu/select until the apple icon appears, at which point it restarts, but the ipod still appears without any access to the music.
My ipod is set to sync manually, i.e. i dont have it backed up on itunes.

Answer 1

It is a big risk to keep your only copy of song files on an iPod.  It can become lost, broken, or in need of a Restore.  That's what your iPod probably needs now, a Restore.  There is probably data corruption on the iPod's storage.
Your computer seems to still see the song files on the iPod, so you may be able to off-load them to your computer's drive.  You cannot use iTunes to transfer song files from iPod to computer, except for songs purchased from the iTunes Store.  However, there are third-party methods and utilities that can transfer from iPod to computer.  If you do an Internet search on something like "ipod transfer," you should get some links.  (The CNET article seems to be popular.)
Once the song files are on your computer's drive, add them to your current iTunes library.  Then (after confirming all of your songs are there), do a Restore on your iPod.  The Restore button is on the iPod's Summary screen in iTunes.  This will erase the iPod, reinstall its software, and set it to default settings.  You can then sync your songs back to the iPod.
Going forward, you should keep all of your songs in your iTunes library (not just on the iPod).  And then back up your iTunes data on the computer, along with your other valuable personal data, to protect against your computer failing.