Remove the casing, then remove the cover over the top of the DVD lense/drawer (held in by two screws, and has a caution sticker on it, if i remember right), power the DVD player up and press the open/close button the drawer should slide out and with a very gentle pull whilst it is opening will pull out from the front of the unit. You should then see what looks like a small blue lever, this is the problematic switch. I then disconnected power from the unit again, and with a vacuum and a clean/new paint brush removed all the dust and fluff from the unit. Powered the system up (

DO NOT LOOK AT THE LASER

it lights up in the next step) and pressed the open/ close button whilst working the switch by hand, after a few attempts the switch worked as it should. I simply then placed the drawer back into the unit, by lineing it up and pressing the close button (If it doesn't close fully it hasn't lined up right, don't try to force it there is a channel on the bottom of the drawer and a sliding pin on the unit that have to line up). I am typing this all from memory so I may have missed something. If you have any problems though just drop me a PM.