If you are running an Apple Bluetooth keyboard and/or an Apple Bluetooth Magic Mouse inside Windows in Bootcamp you may find that periodically the keyboard and/or mouse will switch-off. This is something that can be easily remedied if you know where to look...
In Windows, open Device Manager - screenshot below:
[Note - name of computer, keyboard and mouse have been obscured deliberately]
Right-click on Bluetooth Radio (highlighted in above screenshot)
Make sure that "Allow the computer to turn off this device to save power" is unchecked.
Next, look at "Human Interface Devices" and "Apple Wireless Mouse". Again, make sure that "Allow the computer to turn off this device to save power" is unchecked.
Finally, look at "Keyboards" and again, ensure that "Allow the computer to turn off this device to save power" is unchecked.
End result will be that this issue is resolved and you can continue to use your Magic Mouse and Magic Keyboard with Windows running inside Bootcamp.
You may already have looked at these links: