ok im having problems playing songs i already had

i already had songs in my collection from before i downloaded limewire, now i got limewire and got songs and things, they work fine... i go into my library and i fix some of the song's information (like genre from rock to hard rock) and now whenever i try to play these songs it tells me they are corrupted

i did it with ALL of my disturbed songs and now they wont play at all, i dont know about any other songs in my collection though, but those i know for sure