I just received a nice iBook G4 800. It only has one flaw: the trackpad works erratically when I turn on Trackpad Gestures > Clicking. Even though I selected "ignore accidental trackpad input" it still is odd. If my hands are anywhere NEAR the trackpad while typing, the cursor just flies off somewhere unwanted on the page. It is insanely over sensitive. How can this be fixed? Love the iBook otherwise. Trackpad is better when I turn off Gestures > clicking - however that means I have to use the clicky-button behind the trackpad which plays havoc with my carpal tunnel (and no, I can't use a mouse, I lose feeling in my hand from a mouse.) Help? (running os 10.4.11 tiger)
If it has a clean system installed since you received it, it would not be related to a system extension conflict or something running in your user account (unless you installed third-party software since the clean install).
I found this Apple article, with more possibilities (including some things already considered).
Three items may be relevant. One is Reset the Power Manager (PMU), which is this procedure
Another is to apply a "teflon" trackpad surface protector, which may make it less sensitive. The last item is a possible hardware problem.
I'm going to google to see if there are any sorts of external trackpads that might plug in.
Have you considered a trackball, such as the large square one made by Kensington. It seems to be popular with people who don't like the using a mouse due to repetitive stress.