Dvd player wont play dvds

Question

i tried to play a dvd and the display says "blocked". i dont know what it means or how to fix it..i cant find anything in the manual. ive tried turning it off and on and even unplugging it. i thought maybe it was the new dvd. but it wont even play my old ones. its a magnavox 5 disc dvd/cd,stereo , surround sound thingy... mrd310. i just bought it in january so ....i dunno.. if anyone can help..:(