From what I've been able to gather, this might be just a driver problem--not surprising, considering the challenges I've encountered re-installing my drivers after having to replace my hard drive (thanks, ejn63!)--but I've also seen a few suggestions to replace the palmrest assembly.

When striking the integrated left-click button, I get nothing at all, from what I can tell. However, when doing quick taps on the touchpad itself, it indicates a left-click button locked in the 'on' position in the icon in the right side of the tray to the lower right of the screen (the teal-colored left-click button on the icon is 'on').

Full mouse functionality. Ideas?