Chosen Solution
Not sure what is causing this but only started since upgrading my Mac Book Pro to OS Lion but also hot weather here. As computer gets hotter I lose control of both the mouse and trackpad. Have to shut down and let cool down before problem clears. Then wait and restart. Works OK until warms up again then starts all over. Tried having a fan playing over the computer and lifting computer onto a open frame to allow air to get under it but still problems. Any ideas. This didn’t happen last year when the weather was even hotter than now.
Look if your battery bulged. When so, pressure is applied to the little board underneath the trackpad causing problems. Check if the problem persists without the battery. Occasionally the USB controller fail on these boards which also leads to loss of trackpad / keyboard response.
You said it started after you installed Lion but then stated it happened last year, which rules out Lion problems. It probably needs to be taken down to the heat sinks and the vents cleaned out and a new application of thermal paste. Please give the last three figures of your serial number (found in the battery compartment) and we can exactly identify your machine and get you to the correct guide.
