I believe Windows Media Player won't play DVDs unless another DVD player program is installed. It then borrows the latter's DVD decoder. I'm not sure why you would only get this problem with the guest account turned off.
Alienware 17 R4 2017 review
These brilliant Lego posters show just what children's imaginations are capable of
Mac power user tips and hidden tricks
Comment réinitialiser votre PC, ordinateur portable ou tablette Windows ?