can't add music to itunes library

my hard drive was about to die and I backed up my itunes library in several places. Now when I try to add my music back to itunes (new hard drive), it adds only a handful, and it ignores most of my songs. The few that were added play only noise. I tried reinstalling itunes, but it seems that my song and video (TV shows) files got corrupted during the process of back-up. Is there any way to recover them?