Bluetooth is not working..

Hi, In my laptop (Dell inspiron 1525 I installed windows 7 previously it is installed windows vista) Bluetooth is not working. I tried to install Bluetooth drives it shows an error "you uninstall currently installed Bluetooth drives " but i tried in device manager to uninstall there is no Bluetooth drivers over there. plz help me how to uninstall and re-install Bluetooth or make my device to enable Bluetooth... ?