One of my friends came to me with a problem… “Why did my DVD drive disappear in windows 7?”
He could eject the drive using the button, insert a dvd… but that was it… nothing was prompting him to autoplay. I checked and verified that his dvd drive was not visible under device management. This means 2 things, the cable had gone bad or the drive is faulty. It was getting power obviously but there was no interaction between Windows 7 and his DVD drive. This begged the question.. “have you tried restarting?”… he did and the dvd drive was back!
Solution: Power cycle your computer. This means shutdown and then boot up.
Additional reading that may or may not help: http://www.tomshardware.com/forum/255392-32-optical-drive-disappears-windows