The key labeled Pause on top with Break below that is more difficult to press down than the other keys. I have tried pressing it multiple times in case it needed to be broken in but I didn't detect any change. Also, I don't know if it is Windows 8 or not, but the combination of pressing the Windows and pause keys together doesn't do anything that I've seen. It looks to me like the key is rubbing and farther toward me than the other keys. I have not dropped my laptop or spilled anything on it, and it was bought new. I actually got it last year as a birthday present.
The computer is an Acer Aspire V3-771G-9441. It was manufactured on February 28, 2013. It came with Windows 8 but I installed the Windows 8.1 update. I have the serial number and SNID written down and available in case they are necessary.