My HPprinter icon in my dock had a question mark on it and would not open, so I dragged it to the desktop and it disappeared. Now how do I replace it? I have looked in Applications in Finder and cannot find another printer icon that is the same as I had. I even went to Apple System Preferences and went to Print and Fax and tried to drag and drop the icon picture from there. It did not work. And Time Machine does not work with the dock. Please help.