Sudden Bluetooth output problem

I put my Sony DR-BT50 bluetooth headset on like numerous times before and it automatically connected to my computer running Win7 Ultimate 64-bit with an USB bluetooth adapter. Everything seems to be fine and the headset is selected as output, just that I can't hear any sound from the headset. All options seem fine, but all I hear is a very low, barely hearable buzz as you usually do from speakers not playing anything.

The weird thing is, that this indeed happened suddenly. The headset was recharging and when I took it back to use, nothing. I can't remember adjusting any options that could affect this either, but let me know if there are some that could cause this. Microphone works just fine. Also, the output works through my audio-in -> bluetooth adapter.

 

I've been able to pinpoint the problem a bit. This only occurs with the low-quality handsfree function, not high-quality stereo output.

EDIT: Mumble also says that it's unable to recognize the input and that the audio path is not determined.

 

I got it fixed yesterday by installing Broadcomm's Bluetooth updater or something like that. It worked fine until I went to sleep. And now, the next day, it's broken exactly like it was yesterday. Seriously, how is this possible...