Follow these steps to explore and set a playback/recording audio device in Windows XP:
1. Click on “Start” > “Control Panel”.
2. Under the Control Panel, Click on the Switch to Classic View, and select “Sounds and Audio Devices”.
3. Click on “Audio” tab. Under Sound playback > Default device, select the Avantree audio device you are using. Under Sound recording > Default device, select the Avantree audio device you are using.
4. Click on "Apply" followed by "OK". Then restart the computer.