Trackpad (+ spotlight) semi-unresponsive, Mavericks on a 2010 MBP
If you physically cannot hear/feel the bottom of the trackpad actually click the switches on the right and/or left of the trackpad, then this is probably a hardware issue that only coincidentally occurred with the software update. I have experienced a large number of older MacBooks with failure-to-click issues that are the result of a bulging battery pushing on the back of the trackpad assembly. 

A short-to-medium term solution is to use the "System Preferences" -> "Trackpad" controls to turn on "tap-to-click", but eventually the battery will need replacing. This will have the added benefit of giving you a longer time-between-needing-recharging compared to your four year old battery.