Ok, so my 2142 disc doesnt work anymore. I place it into the optical drive and when i double click on the drive icon in My Computer, it says that the drive is not accesible and its due to an I/O error. whats an I/O error? And yes i do hav a DVD drive. 1 therory i hav is that when u install a game on to may pc's it will lock up and not work. I hav installed it on many pcs, is this such a thing?

plz help
ty