[Ti] Trackpad freezing

[Rafe Day]

My apologies if this is a common issue I should know about, but the trackpad
on my Tibook has recently begun freezing and I was hoping to find a simple
fix for this annoying problem.

Description: 800 MHz PPC G4, 1GB, OSX 10.3.9
Trackpad either (1.) becomes sluggish and only responds to excessive
pressure (and then not very well); or (2.) freezes entirely.  Keyboard
commands always work, even when the trackpad freezes, so I can cycle through
open windows and save work before restarting.  Upon restart, the trackpad
usually works.  If I completely disconnect the power and remove the battery,
it always works for a time on restart.

The problem is intermittent.  It sometimes goes for a couple of days without
reappearance.  But it recently has been happening several times a day.  It
appears to run in streaks -- i.e., happening several times in a row after
only a few minutes of work, followed by a few hours of normal operation.  It
also appears to happen more frequently with certain applications (with a
variety of web browsers and with MS Office components).  It also happens
more often when I'm switching between applications.

Any insights are appreciated.  Many thanks.