windows will have loaded its own driver.
what your missing is the dvd decoder software.
download the trail version of power dvd
http://www.cyberlink.com/multi/download ... 1_ENU.html
install that on your computer and you will be able to watch a dvd film from power dvd till the trail ends and also by windows media player as media player does use the power dvd decoder.
little tip when the trail ends media player will still play dvds