Did someone in your family sync a new ipod with your library or something?
I dunno. I'm not computer minded at all.
Are the files still there if you look in the actual Music folder on your computer?
(Or wherever you usually keep them - I'm guessing you either had them all automatically copying to the Itunes folder as you added them to the library or they should still be somewhere else where you added them manually).
Have you got a file anywhere with the name 'iTunes Library (Damaged)' anywhere? Maybe in your iTunes folder?
Is your music still on your PC?
my music is still on my pc yes, but not all of it?
How much seems to be gone?
Have a look in the recycle bin and see if it's there - if it is, try and restore it.
Well you say its not synced.. so... you're library might still be there.... just go import it again.. see what happens.. if you dont see a library........its either damaged or you deleted it
and this is why, if everything is on your iPod, you need to get everything off your iPod if there's stuff missing on your computer. A lesson learned, I would hope - it's a shame more people don't know it though.