All of a sudden my color picker stopped working. When I click on the color box and point to a color in my image nothing happens. The only way I can change a color is to do it through the big color box and move manually to the color I want. Up until a couple of days ago, it worked fine.
That sounds like the sort of problem a Preferences reset might fix. Hold down Shift Ctrl Alt (Shift Cms Opt) as you start Photoshop.