Solved problem: From another post on the font size error I was directed to go to my windows user directory and in the arduino folder edit preferences.txt. Found the editor.font line had specified font of 0. I had somehow zoomed in on the sketch when I last edited it so that it was so small I couldn't read it. It saves the font setting automatically when you close the sketch. Changed 0 to 12, saved the file and all is well.