It’s all possible via small registry trick in the leaked copy of the update
Believe it or not, but some users are already looking for instructions on how to get rid of the Shut Down button from the Windows 8.1 Update 1 Start screen even though this has been one of the most requested features in modern Windows.Leaked copies of Windows 8.1 Update 1, which are currently installed on quite a lot of computers out there, come with this feature, as Microsoft has tried to make its Modern UI a bit more intuitive and easier to use for both desktop PCs and tablets.
But in case this new power button on the Start screen isn’t quite your cup of tea, WinAero has discovered a very small trick that makes it just a piece of cake to completely remove it.
The only thing that you need to do in order to hide the power options from the Start screen is to create a new registry entry that modified the default configuration.
First of all, navigate to the following path:
Create a new DWORD entry, call it Launcher_HidePowerButtons and set the default value to 1. Reboot the system and that’s it.