I have a problem with playing DVD's in my computer.Some DVD's which was working fine until 2 weeks back have suddenly stopped working on my system.Even though LED's glow on the drive for sometime showing it's trying to read the dvd but then it stops and nothing happen's.Iam not getting any error also.I having the same issue in windows also with same DVD's.I don't know whether it is a virus or a problem with my dvd drive.Although many DVD's are working fine on the system.Is there any dvd recovery/diagnostic tool to find out the problem?.Iam using ubuntu 8.10.