Why does the icon for the arduino software not show up anymore?

I've had arduino software on my computer for a while now. I week or so ago the icon for arduino stopped being displayed next to the program name in my computer's start menu. If I browse to arduino files in a folder, they still display the arduino icon. However, the actual arduino .exe doesn't have that anymore. Instead, all I get is a broken icon image. I have two questions. How could this have happened? and How do I fix it?