If you've uninstalled anything related to bluetooth in the add/remove programs list, then boot to safe mode by tapping F8 as soon as you turn on your computer. Open the device manager by right-clicking on My Computer and selecting manage. Then click on device manager. Find the bluetooth device category and uninstall any devices listed in there. Restart and try the dell drivers again.

You have to uninstall the BT thru the windows update screen>Open windows updates>click view update history>Now at top of this next page click installed updates>Now scroll thru the list and find the windows Bluetooth driver single click to highlight it,and click uninstall.