Not quite sure what you mean by brightness/contrast 'TOOL' because I don't know lots about PS7 -I only know the one in 'Image>Adjustments' . But I was stuck with a tool setting once and couldn't change it until I reset all Tools to the default settings through the tool menu . Is that what you mean ?

" Try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations."
-Monty Python