my laptop computer with a dvd rom will play some dvd's but not all... the ones that wont play dont even register in the player and in windows explorer it shows nothing on the disk. the player also says no disk. i have tried other software, cleaning drive and discs. if i put the dvd in my friends laptop it plays fine. this is not the only trouble i have had... in the past i have been given "cyclic-redundancy check" errors while installing various programs. i would like not to have to replace my drive, are there any other solutions?