SO annoying!!!

Go to D:\drivers\VGA\Intel\x64\9.17.10
Click Setup
Follow prompts to reinstall driver

In this case the button in question was F11 or F12 - I'm not sure which because...accident. These are the screen brightness controls on my Lenovo laptop, and are meant to be adjusted, except for that touching them causes my screen to dim way down and cannot be adjusted back up. Reinstalling the driver is the fix.

Stupid.