Lost Music

Yes, I to have lost music. They are still in my play list but will not play. The problem is that I have lost about 22 CD's worth of music and on some of the CD's I have only lost a couple of songs. I have tried re ripping the the CD's but I still end up with the same result. i tried Alex's repair but, when I go to advanced there is no " consolidate Library" there (Delete or Edit for 15 minutes)