I started using my desktop PC this morning to discover that my Windows key (to open the Start menu) seems to have become intermittent. That is, whereas it used to display the Start menu every time after a normal "tap", now I have to press it a couple of times, or hold it down for a second in order to get it to show the menu.
At first I thought it might be a problem with the batteries in my wireless keyboard, but changing the batteries made no difference. I'm not having a problem with any other keys, and the Windows key seems to work fine in combination (for example Windows-Tab). I've also tried plugging in a wired USB keyboard, and that suffers the same problem.
Intriguingly, if I launch a Virtual machine (using Oracle VirtualBox) and go full screen, the Windows key works as it should within the virtual machine.
I've tried Microsoft's "How to Enable the Windows key" quick fix, but that made no difference.