The PC is not able to play sounds, because the 3G device is disabling the audio card. This is a common issue encountered by many V-cell 3G Data Card users. In order to fix it you will need to enable it every time you uninstall and reinstall the V-cell 3G Data Card. To do this, you need to right-click the sound icon from System Tray and to open Playback devices. Right-click anywhere in the opened tab and select Show Disabled Devices. Select your sound card, click Set Default and then press Properties. From the Device usage drop-down list select Use this device (Enable), press Apply and then OK.
