I reformatted my laptop with it's original medion/vista discs, since them it wont play dvd's, windows fixit says unrecognisable media in dvd player. Strangely also behaves exactly the same with external dvd player. Both of which work fine in my other laptop. Machine shows are dvd playing enabled and working with up to date drivers, and no upper/lower case reg issues. And it clearly boots from disc when under bios control, so fairly confident player working, leaving a windows problem, and one that windows can't detect.