If rebooting doesn't clean it up might check your Fonts Folder, maybe the Font you have set for the display has become corrupted or is missing and the substitute doesn't display correctly.
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Customs, Dell, Gateway, HP, Toshiba, Acer, ASUS
OS
Windows 7 Ultimate 64-bit, Windows 8.1 64-bit, Mac OS X 10.10, Linux Mint 17, Windows 10 Pro TP