Enable Windows themes (for proper VSync - eg tearing issues)
Try the following in the dcmediaplayer.ini:
[dshow]
useinternal=0
usevr=(try switiching between 1 and 0)
usevmr=(try switiching between 1 and 0)
Ensure graphics drivers are up to date.
Check if hardware acceleration options are set.
Check the codec pack installed on the player.