my itunes deleted itself

[450raider]

ok ive been having problem after problem with my computer for the past couple of months but this one hits a little below the belt now weve have or had a pretty nice little itunes collection built up with more stuff bought and waiting to load when we had time, but a few days ago i went to listen to it or make a cd or somethin and everything ever done was just deleted and when i searched my music files i found 2 that said "itunes library" only 1 said damaged beside it so i tried both by "open with" itunes and still nothing pops up so is there a way to fix the "damaged" one?

thanks for any info