having problem on Win 10 on new computer

Just loaded the latest version 15.3 Mega on a new computer running Win 10, When I click on a mkv file it takes too long to load and then it freezes and will not play. Any idea what I should look for??? I will try an avi file later today to see what happens

Those symptoms are usually because of a problem with the graphics driver. Which graphics card do you have?

Disabling hardware acceleration in the video decoder settings may fix playback. But this is just a workaround for driver bugs. For example recent AMD driver have some issues with hardware decoding on RX 5700 cards.

I solved the problem after trying another video player.  I tried VLC and got the same results, no picture, just a blank screen but I did notice that the video seemed to be playing as the bar at the bottom of the viewer was moving from left to right.  So I decide to see if it was producing audio.  I plugged in a set of headphones and the video came on.  I then went back to MPC and there was the video.  Seems it did not wish to display without an audio device connected.  However after it initially displayed the video I can unplug the headphones and the video will still continue to play.  Strange set of events, but all is well now, the board is a Radeon Pulse RX 590 8GB GDDR5 if that will help anyone in the future.

Thank you for your response.

Interesting. A problem with the audio renderer can indeed cause playback to not start. But I would expect the device to work even when no speakers/headphones are connected.

Check if the "Speakers" device is set as the default audio device in the Windows Control Panel. Sometimes the HDMI output from the GPU gets set as the default device and that can cause problems with playback.