Key Protection?! Cant playback DVD's

[vashz]

hi all


Just got my DVD burner (sony DW-U14A) and now I cant seem to play back and DVD's...

I have tried Windvd/powerdvd/WMP/Media Center and none of them work.

In windvd the dvd plays but there is no sound or picture....

Powerdvd just crashes my machine and reboots.

in wmp I get the following message:

Windows Media Player cannot play this DVD because a problem occurred with digital copyright protection.

and in Media center I get:

Key exchange for DVD copy protection failed. Unable to play back this DVD


Whats going on?! and how do I fix it?

Thanks to all who respond.