Brightness/Contrast stopped working

In Windows PS 7.0, When I click on Image>Adustments>Brightness/Contrast the cursor turns into an eyedropper and the box for the slides for Brightness and Contrast does not appear.
And it appears that pretty much everything locks up.., can't event X out of the program and have to use Control/Alt/Del.
I have asked several folks that know PS 7.0 and they are lost as well. Any suggestions

Sounds like the dialog box is off screen.

Maybe you changed your monitor's resolution or switched from 1 to 2 monitors recently?

A reset of the preferences should fix it

That was the ticket. The box was off the screen. I changed resolution and put the box back where it belonged
Thanks a million.
Rick