I have a 17" Macbook Pro 2011 and use my wireless keyboard daily. It's great and I've had no issues until recently. At first I noticed that the right CMD key didn't work, then the tilde / ` key as well as the § key. All my other keys work. I realise it's possible that the keyboard is faulty and want to know is there any way to "reset" the keyboard or any additional troubleshooting step that can be taken to be sure that the keyboard is due for replacement?
I think what you have is a worn out keyboard. I've had a keyboard do this to me. More than one actually. I'm a writer by the way. And since 2011 if you used it daily, that's a lot of keystrokes. Not only wearing out, but the key pads - the contacts inside - can develop corrosion. Kind of like rust? but actually just grime can slowly coat the surfaces inside and stop the contact being made when you press the key. Try borrowing another keyboard. I don't think they can be repaired.