I'm able to left-click when using the mouse keys. I'm able to navigate, scroll and right+click with the mouse. I disabled the trackpad when the mouse is plugged in under Universal Access, but I still am unable to get the left-click to register with the mouse. When the mouse is plugged in, left-click doesn't register. Sporadically, I have some left-click function with the trackpad and mouse when the computer is awakened from sleep, but not always and never for very long. I'm able to navigate with the trackpad, but the click doesn't register (the trackpad does physically click). Very soon after, left-click stopped working.
Instead of clicking, it would click + hold (selecting all text). My trackpad began malfunctioning suddenly.