well, right click my computer then properties then click on the hardware tab.
then click on device manager. once you have that open click on DVD.CD drives and see if its listed. If it isn't up at the top of the window click on actions, then check for hardware changes. Basically your wanting to reinstall the DVD drive like its a new one. If it is there then click on the update driver and see if that works. if not let me know, there are other ways to try fixing your problem