I have installed my drivers and paired the device up to the computer. I have given it a quick run through on Steam Big Picture mode to make sure it's all working and behaving as I'd expect it to, but now I need to spend time doing something else. I have exited Big Picture mode but my Wireless Xbox 360 Controller for Windows has remained powered and doesn't seem to want to switch itself off.
I have tried holding down the Guide button in the middle of the controller, which is how I switched it on in the first place, but this doesn't appear to do anything. I also can't find any other buttons on the controller that would seem to affect whether the controller is powered or not.
How can I turn off a Wireless Xbox 360 Controller for Windows?