Hi i have a problem with my dvd rom. It seems that my dvd rom malfunctions. Sometimes it can play dvds, while it usually cannot . After i insert dvds into the device, my pc usually doesn't recognize any. Then i play the dvds that i have inserted into my pc on another computer, but the computer does not recognize them either. My dvd rom used to be able to play the dvds, and the dvds were not rewritable so virus infection can be ruled out. Please advise.