No clay/tone in the Headset despite connection

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The following problem:
the connection between PC (Tablet PC, WinXP) and Headset functions. I do not hear only no clay/tone and the micro functioned. In the system control (characteristics of sounds and audio devices) the equipment volume is set to zero and expenditure-has a horror, i.e. I cannot place louder…
The Headset functions with my mobile phone problem-free.

Headset: Logitech mobile pro BT
Dongle: Fujitsu Siemens of computer Bluetooth USB Dongle

White someone because of which is or which I could try out everything around the error to find?