If your computer sound does work, you may want to make sure you have the correct Audio Output selected for the CQ100 software. You can check and/or change the setting by clicking once on the '?' in the upper-lefthand corner of the transceiver. Then, under Transceiver Options > Audio Output, pull down the drop-down box and make sure the correct device is selected. If there's only one shown, post a reply to this forum topic and we'll try something else.