I recently bought a DVD burner from a guy........a Memorex MRX-500N.........I took out my old CD burner which worked fine, but now my computer recognizes the burner is there, but won't let my original (CD-ROM drive D) or the new DVD burner even read CDs. On 'My Computer' it shows drive D, but with a CD in it still says 'insert disk'. My DVD Burner doesn't even show up on 'My Computer'......and of course discs don't read from it. My old CD burner was drive E. E no longer shows up. I didn't get any installation software with the new one. What do I do?