If you are getting constant dirty disk errors, what do you have to loose, give this a try. The majority of the drives are not really dirty cleaning it will not fix the problem, they are getting out of adjustment or just getting weak. Try not to get your hopes up, too much sometimes you will be improving a DVD from constant errors to less frequent glitching and pausing during movies and games. But I guess that is better than nothing

Words of advice before we begin, leave the small ribbon cables that connect components within the drive alone. If you feel you must disconnect and reconnect a few while you are in there, note that there is a brown wedge in each of the sockets that needs to be pulled out to allow the ribbon to be released.

There are four screws that need to be removed. Two in the rear

and two in the top, mid drive

Remove all four screws, the ones mid drive are a little hard to get out, screw grabber makes it easy, shaking the drive upside down works too.

Remove the bottom tray first, flip the drive so the bottom is facing up. You need to pull the metal tab in the back over the IDE connector and then it will then slip off. Pull out then up.