Trackpad Makes "Click" Sound, but Does Not "Select"

Mid 2009 17” MacBook Pro

Full disclosure: I know nothing about computers, and this is my first attempt at computer repair. I have been combing the forums, and am thankful for the guidance everyone offers!

Recently, the trackpad stopped responding to left clicks, but would allow right clicks, and the cursor worked as expected (this was also the case with a USB mouse). I knew the battery was beginning to bulge, so I replaced it. After replacement, the computer no longer responds to left or right clicks (same result with the USB mouse). I can hear the click, and the trackpad moves up and down with each click, it just will not select. Cursor responds perfectly.

I have cleared what little visible debris was between the original battery and the trackpad, tightened the screw in the trackpad case, and even gave the trackpad a medium-force whack, as a last resort. Still no luck. Is it time to replace the trackpad, or does anyone have another suggestion?