video Files on DVD corrupted
 

Hi there,
Strange, slowly over a brief period of time videos I kept as files on a
DVD stopped playing. Even if I move them to my hard drive they will
not play. They ALL use to fine, but then over time thumbnails started
not to show. Even now the moment the comouter tries to detect the
thumbnails on the DVD, it crashe windows explorer.
So any idea what happenned? Is there a way to "detect" corrupted video
files? Repair?