I have a Bluetooth adapter and a Bluetooth headset connected to my pc. When the headset is connected I can't control the volume on the PC. I stays at 30% which is were I usually keep it when using my stereo speakers. When I adjust the volume control slider, the volume in the headset doesn't change. It was working fine and just started this all of a sudden.
On windows 7, I'm unsure about other windows but i'm sure it is similar: If you right click the sound icon and choose playback devices, go to your Bluetooth headset choose properties and check the levels on it, you should be able to change the volume from there.