I use GOM Video players and under options it allows me to select aspect ratio which for flat screen 1080P 16:9. It also allows be to stretch the picture with degrading the picture.
Look on the graphics control center and you should see an option to overscan,push this up untill it fills the screen. It`s on the catalyst control center for amd gpu and nvidia has somthing similar.
I`ve never used win 8 but Ill try to explain,if you have a task bar where your antivirus shows up in the bottom right hand corner check there,if not try right click on the desktop and you should see a option pop up and you are looking for nividia or catalyst control. If your laptop has intel graphics it might be under intel.
I use GOM Video players and under options it allows me to select aspect ratio which for flat screen 1080P 16:9. It also allows be to stretch the picture with degrading the picture.