Problems watching movies on computer

[Morphghost]

I don't know why but when I play certain movies on dvd via computer, they never show up for me to watch. A majority of my dvd's work but there are a few that don't. I attempted to reinstall the DVD reader driver but that didn't work either. How can I fix this?

 

[carnageX]

What software are you using to try and play the DVD's? Or are they not even being recognized in the computer?