I have a I/O device error on my DVD player on laptop,trying to play a DVD movie,in Media player,no movie,Why?

The laptop has Windows X/P,the device manager says the drivers are installed and device working properly.Windows Media can play music from the hard drive but no movie.there is a I/O device error message.Windows Media does not even see the movie in the DVD drive.What is the solution to the problem?Do i need to download updated "Decoder" drivers?The region is set for region 1 USA.