Two things you should try before bringing it to repair.
First, unplug the machine for 5 minutes, then plug it back in and try playing a dvd. Try this routine also with a cd. If result is no success then buy a dvd disk cleaner from a dvd/cd store and clean the reader lens. 
If it still doesn't work take it to an electronics shop and get a repair estimate.
                
 Bounce4809
                
 February 2009