I had a google around and it sounds like the Photoshop Elements Preferences file needs resetting the easiest way to do this is:-
To hold down the Ctl-Alt-Shift keys before launching elements (keep this pressed until it has launched), it should ask you if you want to delete the preferences file.
I got this information from
here
You can manually delete the file but the location of the varies depending on what version of WIndows your using or if you are using an Apple computer.