Ok, I have my whole music collection on my iphone (Iphone 5 running almost the latest version of 7 though today it has started telling me there is a new one). Somewhere between the night before last night and last night, something happened and like maybe 50% of my songs got corrupt (I don't know, a lot of them got corrupt or something, it greys them out now and puts a red stop symbol next to them and will quickly skip them if it comes on one when I have it on shuffle). Some are ones I didn't purchase through itunes, some are. I tried restoring it to my last backup (which was 6 days ago) but that didn't seem to fix the problem. How do I fix this (or rather what things can I try)? The songs are fine on my computer (old 2010 Macbook pro 13" running Mountain Lion (10.9.1) and my itunes version is (11.1.4, latest far as I know but I could be wrong).