Since you posted in photoshop elements forum and if the below isn't the problem, you should ask over in
the photoshop general forum where folks are more familar with photoshop cs6
What operating system are you using?
If your on windows i seem to recall some reports of out of date graphics card drivers causing a problem similar to your screenshot.
If your on mac lion or mountain lion it's possible that the cursor size under Apple>System Preferences>Universal Access>Mouse and Trackpad
is set to something other than Normal.