To disable Bluetooth follow below steps:
- Go to Start menu -> Control Panel
- Click on Device Manager to bring up Device Manager Dialog Box
- Under devices tree you will find the name of Bluetooth Device ( in my case it is Dell Wireless 360 Bluetooth Module)
- Right click on the device and click the disable option from the popup menu
- It will show a message saying "Disabling this device will cause it to stop functioning.". Click on Yes button to complete the step.
After disabling the device you will find that disabled device is marked with a down arrow ( as mentioned in figure )
To re-enable the device you can follow the same steps, right click on the device and click on the enable menu item from the popup menu to enable it again.