Missing .avi files ---- i need some help guys!!! for real! urgent! help!?

well first of all search your system for the files maybe they got moved. if that doesnt work and you think they got deleted go to iolo.com and there is a program that can bring back deleted files. about your sound try downloading some new audio codecs. i had a similar problem but only with certain songs on certain media players. vlc player is my personal fav give it a try.