i'm running a 1.67 powerbook with 1.5 gb or ram and 120 gb hard drive. it's the latest rev. anyway, whenever i have my external harddrive hooked up, everything is choppy. i have to double click a lot of stuff because it doesn't register. my mouse pointer is sort of studdering. anyway, it's hooked up by firewire if it matters. edit: just unhooked the external and everything is still really sluggish and choppy. it's still not accepting everytime i click, causing me to click more then once because it's not registering. i replaced batteries and made sure the mouse settings were correct. i also repaired permissions and did all that stuff. any advice?