How to diagnose intermittent keyboard lockup and mouse problems I have an intermittent problem with my MacBook Pro 15" (November, 2008 vintage). Running OS X 10.6.8. 

Two or three days a week, sometimes more, the keyboard will stop working intermittently (no key presses work) and the mouse will select everything as if I have the left mouse button pressed all the time. I get the same behavior from the built-in keyboard and mouse pad and wireless keyboard and magic mouse. 

Restarting doesn't usually help. Powering down and waiting 10 minutes usually makes the problem disappear for a few hours.

I assumed it was an overheating problem and installed Fan Control. However, the last time I had the problem, the CPU temperature was only 54 degrees C and the case did not feel hot.

I'd appreciate suggestions on how to diagnose this problem. 

This is a company owned laptop and due to a "frugal" employer, I don't have AppleCare.
The problem was the battery was expanding and pressing on the motherboard. I was told by Apple that it is not uncommon for old batteries to expand after a few hours of using the machine. In summary, I just needed to replace the battery.