Are you sure it's the trackpad? Have you ruled out the ribbon cable? Sometimes just re-routing it from under the hard drive enclosure casing to up and over the enclosure casing can correct trackpad problems. Have you tried that &/or replacing the cable with a known good one? A bad pram battery can cause erratic trackpad action as well as an overheating logic board. Is your laptop fan(s) working ok? You can download iStat Pro to check your working temperature. There is NO software to control the DVI's fan speeds, but you can check it's temp.