Topic: fucked up discs????

[1st set only]

hey all,

over the weekend I wanted to break down and listen to some phish, I went through my wifes big cypress colection. I think i remember these discs being the split omni source that a lot of people talking about. they are mitsui brand which i thought was supposed to be very good. anyways they will not play in either my dvd player (which plays anything) nor my dvd drive in my computer (doesnt recognize that there is a disc in side the drive). These discs have no visible damage like flaking or any scratches at all. I know that they work I have listened to them before. any ideas as to why they wont play?