Youíre not the first person to ask this, and you wonít be the last. The answer, basically, is that Windows 8 cannot play DVDs or Blu-Ray disks out of the box.
That is because the software technology for playing these disks isnít free ó Microsoft previously paid $2 for every copy of Windows sold, just for the right to use the patented technology needed to play DVDs . Considering the ever-increasing number of devices without optical drives, Microsoft decided it wasnít worth paying for features many people canít even use. Personally I use DAPlayer, 100% free blu ray software.