I keep my mass folders of mp3s on my external hard drive and play them on iTunes.

I decided to reformat my laptop and also upgrade to Leopard. Everything went fine and I began moving all my folders of mp3s into mew itunes library and again everything is fine until I deleted a folder of mp3s. No problem I just re-downloaded the same package of mp3s as the last and when I dragged the folder to its proper library and iTunes won't accept them. I've tried downloading the mp3s from other sources (all Bit torrent if this is significant) and it still won't recognize them. The files show that they are mp3's and it should work.

The only mp3 files that work are the ones on my external. No new downloaded material at all. What is even odder programs like VLC won't read them either. But at least VLC gives me an error instead of ignoring me.

I can't think of what is wrong. I thought it was a faulty download but all the other material I have downloaded can't be recognized either. Does Leopard need a special codec? And it appears as if files from Limewire will play on iTunes.

Sorry for the long post. Please help me.