Did you set the resolution correctly in File > Build Settings > Player Settings? The game window does not have anything to do with the build and does not affect it.
Also try to delete the PlayerPrefs. I currently don’t have Unity running but I think I saw that option in the top menu. If there is no such option, create a new script, attach it to a game object. In Awake, you clear the PlayerPrefs. See here. Start your game, then stop it. Build your game, and check if the issue is solved. You may remove the script afterwards.
If the issue persists, maybe you could follow Rob’s instruction in this thread. If you are lucky, there is a helpful error message in your browser console.