Yesterday, I reformatted my Lenovo G580 laptop, and ran a clean installation of Windows 10. After the installation Bluetooth disappeared completely. I waited till all the updates are downloaded and installed. However, this did not install the bluetooth driver. Note that before this clean installation, I was running Windows 10 with Bluetooth perfectly working.
The Bluetooth disappeared from Device Manager. There is no entry containing Bluetooth in name, including the hidden devices. I tried to install the drivers from Lenovo's support website. As there are nothing available for Windows 10, I tried to install the ones for Windows 8.1, with compatibility mode set to Windows 8. But none of those drivers were installed due to the following compatibility issue.
Realtek Bluetooth suite can't run on Windows
Device does not have bluetooth
Bluetooth is not available on this device. Please try using an external adapter to add Bluetooth capability to this computer
Being clueless now, I tried to reset the BIOS to its default settings, as some of the internet articles and/or SE sites suggested. I have already seen this Option to Turn Bluetooth on or off is Missing and tried some of the suggested solutions. But nothing worked.
Please advise on how to solve this problem?
Additional details: I tried Ubuntu with a bootable USB, and bluetooth worked there like charm. However, when I logged back into Windows, it was still the same (no bluetooth).
Solution worked on my machine: I finally solved it by updating BIOS from here. I rebooted after installation, and the bluetooth is there in the device manager :)