i want to know whether i need to install WIDCOMM drivers that came with BT device
or should can install drivers provided by NOKIA NCF BT drivers
so that i can program my bluetooth DEVICE
If the only use case for your Bluetooth USB device is to use it as a Bluetooth HW for the Nokia Connectivity Framework, then you do not need the Widcomm driver.
If you happened to install the original Bluetooth driver, it might happen that even though you had meanwhile installed the NCF driver, every time you insert the dongle again (or start your computer), the original driver is detected and installed. In this case you just have to reinstall the NCF driver.
If you end up in the never-ending loop where the NCF driver cannot be installed, the only way to install it is to go to Control Panel | System | Hardware | Device Manager | Bluetooth -> Properties (the mouse's second button) | Driver | Update Driver -> choose Nokia -> NCF driver from the lists.