How to turn on/off Bluetooth on Windows 8.1

Well, it seems that luckily they have fixed this in RTM:

Another simple method is to right click on WiFi or internet icon and click "Open network and sharing center". On the left panel click on "Change adapter settings" then find and disable "Bluetooth network connection" it is off!

What you have to do is right click on the Bluetooth icon then click on show Bluetooth devices then the switch is displayed.