Look in your hardware profile in control panel - the tracker pad will probably be registered as a generic serial mouse, or something like that. If you stick in a USB mouse, you'll see that too as a generic usb mouse. You should be able to disable interrupts on the generic serial mouse, but probably only with a usb mouse installed (it probably won't let you disable the tracker pad if there's no other pointing device detected). If you can't disable interrupts, you can fudge it by shifting the interrupt range above 0x7FFFFFFF (i.e. make it a 2's complement negative number) - that should set the effective interrupt to null.