Eye Dropper Tool

Hello, I am relatively new to Photoshop an whilst attempting to learn an teach myself i hurt my hand in an unrelated accident, I stopped at took a break for a while an am back now only to open Photoshop an find things are not as I had left them prior to this I have had no issues and have changed nothing. When trying to edit an already existing photo an capture a color hue using the eye dropper tool when I try an go anywhere over the image I am given a prohibited sign  of a white circle with a horizontal line through it, I have never seen this before an am unaware of how to fix this I thought it might have been the photo an went ahead an downloaded one provided by Adobe for practice manipulation an am seeing the same thing, and lastly, now my brushes an presets are all one the upper right hand side when before they were on the left, all the "tools" are still on the left but when i click the paint brush it shows settings on the right now. Hope this makes sense... Joe