Windows 8.1 product key update?

So I just got a message on my computer that says my Windows 8.1 product key will expire soon and I need a new one or my computer will no longer work after January 2nd, 2015. I'm wondering, is this an actual thing? You have to get new product keys every so often with Windows? I never had to before, but maybe this is a new thing. Has anyone else running 8.1 gotten a similar message? If so, how did you resolve it? Do you just request a new key from Microsoft?



Please, no comments about how I should switch to a Mac or other operating system; I'm far too used to Windows products and Macs (and the others) confuse the ever lovin' bejesus out of me as a result. I've tried playing around with Macs on occasion and I can't make heads or tails out of that OS.