This is frequently due to the gears inside getting jammed or off track.
In the front of the drive is a very small hole, big enough to put in a straigtened paperclip. Put one in and it will push the drawer out and open.
Sometimes opening and reclosing it will fix the problem with it ejecting, other times you just trash it and buy a replacement...since they are in the $25 range these days.
OS: Windows XP Professional
Drive: Standard 48x/16x/48x CD RW drive
ALthough the LED lights on the outside of the drive are on, which means that is recieving power, when I push the eject button the cd draw doesn't eject, instead the drive just makes a buzzng noise.