If the symptom is still not resolved even after reinstallation, please check again after changing the settings as follows.
① Go to [Preferences (F5) > Video > Video tab] and change Output Type to VMR9-Renderless Mode or VMR9-Windowed Mode.
② Close the Preferences window and close the GOM Player and run it again.
③ Play back the image.
Also, please delete all installed codecs from the control panel and play them again.
If the symptom does not improve after changing the setting as above, check if the other player is playing normally, not the GOM Player.