Photoshop :: CS3 Tools Dont Work

for a while now, my photoshop tools wouldnt work. it was only the tools that involved "painting" like the brush tool and quick select. after reinstalling, they would work but suddenly they'd stop again. eventually i figured out that it was the pen for my wacom tablet. every time i used the pen, it would make the mouse not work untill i reinstalled the program. this means that a setting changes (pen pressure or something) when i use the pen and it doesnt change back when i use the mouse. i cant deturmine which setting changes.