When I insert a DVD (in good condition) into the iMac (less than a year old) DVD slot, it will not go all the way in and the Mac does not sense that I am trying to insert anything. It feels like it is hitting a spring of some sort that is preventing it from grabbing the disk. There is nothing already in the drive. I have reset the PRAM, rebooted with mouse down, but now I don't know what else to do. I remember something like this happened with my Macbook Pro a few years ago, but can't remember how it got resolved.