May be you noticed already, but FWIW:

Yes. I did. Thanks!

Somehow my WiFi adapter broke in Mint. But I can't exactly blame the upgrade to 17.2 as it wasn't working when I booted up my netbook to install the update. But it had been a few weeks since I last ran Mint on that machine, so I'm not sure what I did or what changed since the last time I used it to break the WiFi adapter.

The update worked (when I plugged in the ethernet cable) without any other issues but WiFi is still broken for reasons which are unclear to me. I know it's not a hardware issue because the WiFi works just fine on the same machine in Windows 10.

If you don't mind trying some other distribution's live cds, perhaps that might give some hints too.

That's a good idea. I'll make a live USB of Mint 17.2 and see if my WiFi works there. If not, try 17.1 etc., and go back until I find one that works.

Mint 13 on a decent Lenovo laptop. Wifi dropped connections so often I am only able to use it reliably wired. I posted here about it a couple of years ago (googling 'Mint or other distro wifi not working' was/is a very good indication of the prevalence of Linux and Wifi issues).  The reason I am posting this is I am pretty certain going back version (major ones at least) is probably the wrong way.

I know it worked in 17 and when I first upgraded to 17.1. But somewhere between 17.1 and 17.2 my WiFi stopped working.

It has nothing to do with dropped connections. The Wireless connections thing in the panel is completely gone. I can't even attempt to connect to wireless SSIDs. It's like it doesn't recognize that I even have a wireless adapter in my netbook. It probably broke when I updated the kernel. But those things always confuse me because they warn that they're dangerous (level 5 updates), but they also say they're security updates, so I have just been installing them.

I know it worked in 17 and when I first upgraded to 17.1. But somewhere between 17.1 and 17.2 my WiFi stopped working.

Sorry for the misunderstanding. However Wifi is easily the top 3 issue with Linux in my admittedly limited experience.

Did you check and see if Mint has identified any 3rd party drivers it can load?

Linux Mint 17.2 “Rafaela” Xfce released
http://blog.linuxmint.com/?p=2889

Posting from Mint 17.2 Xfce with perfectly working WiFi. All seems well.