Computer restarts on opening certain files
 

So I have a problem.
I downloaded a series, checked for viruses and all that, but when I go to watch them, the player opens just fine, but once the video loads, the screen goes black and a few seconds later, the computer restarts entirely.
I'm pretty sure they're MKV files and I have version 2.43.

Any idea what could be causing this?

Can be a codec problem i don't know ,try uninstall all the codecs and install K-Lite Codec Pack see if that helps..

Or upgrade your video card drivers.