I had to literally search all over the whole day to get a solution as i was getting extremely frustrated. funny thing is, i just now came about a question in yahoo where the person had used cc cleaner (registry cleaner) and right after that their cd/dvd drive disappeared. well the same thing happened to me but i didnt realize it until a while later since i dont normally use the cd/dvd drive much. anyhow i tried deleting the lowerclass keys in the registry like many people in many places mentioned, well that didnt work.
and then finally after trying out several other fixes and being disappointed, i came across a post in some random forum which saved any further hassle! its very simple. download the free version of Daemon tools, install it and run it. as far as I can tell right after running it i checked my device manager and my dvd/cd rom drive was showing up without any problems! i realized since i had to struggle my way into finding this easy solution that i should also share my solution and save people some time. well i hope this helps some people in the future anyway!