Hello Sushovan-M. Thank you for posting on the HP Forums. I understand you are looking for a Bluetooth Windows 8.1 RALink driver, compatible with this computer. Unfortunately, no such driver exists, at this time. If you return the computer to Windows 8, you will be able to use the computer's Bluetooth feature.
Alternatively, you could try utilizing a USB Bluetooth Adapter. However, I cannot guarantee it will work.
Please let me know if you have any other questions or concerns. I'm only here to help!
Mario