cannot play dvds

hi

i have window vista ultimate ,

8600gt graphic card ,i have samsund dvd drive
but cannot play dvd movies it give error :

"Windows Media Player cannot play this DVD because there is a problem with digital copy protection between your DVD drive, decoder, and video card. Try installing an updated driver for your video card."

i also all software to play dvd like power dvd,vlc,wmp classic ,wmp 11

also i have k lite kodec pack

pls some one help me