Dvd player comes up with pre-stop or inv...

when i place a dvd in the dvd player it reads the disc and either comes up with pre-stop or invalid disc. sometimes it will load a disc as far as the menu and then it will stop and will then say pre-stop or it will say invalid key. cannot get into the set up menu to change any settings but can get into the other menus for either the tv or dvb. help...........it`s brand new and i`m lost.....

paul p