First you go to %APPDATA%, which can be accessed by pressing WINDOWS KEY and R, then typing in "%APPDATA%," then you scroll down to Piano From Above. Double click on the folder, and then edit Config.xml with Notepad. You will find a string saying
Video Renderer="0" ShowFPS="0" LimitFPS="1"
In order to enable FPS, you would set the 0 in "ShowFPS" to 1. For fun I disabled "LimitFPS" to see what would happen. Turns out if you have too much FPS, on a full window, it will freeze PFA, so be careful!
This should still work (May 22, 2017)