Have you tried cleaning the pick up lens and/or the discs? Does this happen with pre-recorded discs (store bought ones)? On those that it does recognise, does the autoplay start first time or do you have to open and shut the drive several times before it's recognised? Also, how old is it? It may be dying and in need of replacement.
You can try removing the upper/lower filters using the directions found HERE .
If that doesn't help you might also be able to go into Device Manager and remove the IDE channel or SATA channel associated with the CD/DVD drive. If you're not comfortable doing something like this, let someone know and we'll try to find a step-by-step for you.