[Low-end PC optimization setting]

An alternative method to resolving this and playing on full screen is as follows:

 

• Turn on Low End Optimization.
• Close the game.
• Go to your Documents.
• BnS Folder
• Right click and Edit the file here called "ClientConfiguration"
• Find the line that says <option name='windowed' value='1'/> and change the 1 to a 0.
• Find the line that says <option name='full-screen' value='0'/> and change the 0 to a 1.
• Save the file.
• Load BnS back up.

And now you have the low end optimization graphics etc. but you'll be playing on full screen, :)