trackpad/keyboard not working

Hello, I have a 2012 13" Macbook Air (I think) running 10.9 Mavericks and yesterday while browsing Internet the trackpad and keyboard suddenly stopped working and haven't worked since. Fortunately a USB keyboard and mouse still work (using them now) and otherwise the computer seems fine (power button still works for turning on or off), though the problem persists after a few restarts and even in Safe Mode.

I kind of dropped my Macbook sometime in the last month, though it wasn't that big a drop, it was on a carpet and the Macbook has a plastic case, so maybe that knocked something loose, who knows. Not sure what the issue is and what to try first. Here's my list of things I'm going to try tomorrow.

1) Back up data
2) Reset SMC
3) Reset VRAM
4) Upgrade to Yosemite (upgrade or clean install?)
5) If that doesn't work, take it to an Apple Store Genius Bar

I've tried browsing other topics but I'm hoping resetting the SMC or VRAM will fix whatever happened. Just checking first if there are any other options. Thank you for any helpful advice.