I have a Dell Computer that I can't copy cds, dvds or even any data to a disc of any kind. The upper dvd rom will play movies but the lower one won't acknowledge anything at all almost like it is disconnected. But when you put a disc in it the light flashes and that is all. I have a upper dvd rom and a lower drive for copying. The drive is a HL-DT-ST DVD+-RWGWA4164B. The computers troubleshooter says it is working ok but it isn't. Can anyone tell me what my problem might be? Thanking you in advance for any help that you might be able to give us.