Try a firmware upgrade dude. I use LG writer for my dvd and it has firmware upgrades. Also check you cables might be loose. Disconnect the power before you touch anything inside and ground yourself before you do. Last check for the latest drivers or rollback on the driver to windows default.
Is there any cd or dvd encryption program running in the backround. Are there any cd/dvd iso imaging programs running in the backround? Many things can cause conflicts if not setup right.
Happy hunting dude.
