So, what do you think is the problem? Is it fixable?
Could be that the gears that make the tray eject are out of alignment -- they're all plastic these days, and it doesn't take much to have the gear teeth skip a notch, and after that things can go squirrely.
(Which is why it's a bad idea to close your drive by pushing the tray itself -- using the button is les slikely to break it)
Look for a tiny round hole on the front of the drive. Get a paperclip, straighten it out and push it down the hole. Doing so will trigger a manual eject, where the front tray will open far enough to be able to pull it out by hand the rest of the way. sometimes that's all it needs to come back to life...
If it's still busted: you can get a brand new 20x speed DVD burner for around $25 or so. In all likelyhood it's not worth fixing your existing one.