Please help; dvd player problem

I never used to have this problem. Now, no matter what dvd I insert into my computer, it won't play on 'dvd player.' it doesn't show up on the computer or in finder, and although it opens up dvd player when i insert it, when i click the 'play' button, it says 'supported disc not available' as if it can't detect the dvd. i know its not an issue with the actual dvds, but a software related problem. any help?