|Did you try right-clicking on the icon in the system tray? According to Dell, this should produce a popup menu from which you can select Disable Bluetooth Radio.|
If that doesn't work, you may have to access the System Setup (BIOS) menu to disable your Bluetooth device. To do this, restart your system and when the Dell logo is displayed, press the F2 key. If you wait too long, you’ll see the Windows logo. If this happens, wait for Windows to startup and try again.
Once you get to the System Setup (BIOS) menu, check Power management settings to see if there’s an option to disable Bluetooth on your system.