While the ooVoo video calling software allows you to call up to 12 other users, this doesn't do you a lot of good if you can't hear each other. This audio problem may be caused by your ooVoo settings or the sound settings on your Windows computer. If another caller can hear you but you cannot hear him, then the issue may be with your speakers or the other caller's microphone. A little troubleshooting can help you find and fix the problem.

OoVoo Settings

Check ooVoo settings to ensure that ooVoo is set to access the right audio components. Open the ooVoo menu, select "Settings," and then choose "Audio & Video." OoVoo selects the microphone for you by default, but you can select a microphone manually if ooVoo did not select the correct device. You can also choose the correct speakers from the drop-down menu in the "Audio & Video" section. If ooVoo does not detect an external device, such as a headset, disconnect and then reconnect the device to see if that solves the issue. If the device connects via USB and reconnecting does not help, move it to a different USB port to see if that helps.

Other Applications

If you have another audio program open, such as Windows Media Player or a sound recorder, is may have overrun ooVoo and caused sound not to work in calls. To resolve this issue, close any other programs that use the microphone or speakers. You may then have to end and restart the ooVoo call for the sound to begin working again.

Windows Sound Settings

The problem may not be with ooVoo at all, but rather with your computer's sound settings. Close ooVoo, and then open another program that uses sound to confirm that sounds do work on your computer. Do a search for "Adjust system volume" on the Start screen, and then open Windows' volume manager. Check that none of your devices are muted; this is indicated by a red circle-and-slash over the volume icon underneath each device. If a device is muted, unmute it and try making a call again in ooVoo. If you cannot hear any sound on your computer, you may have a problem with your sound card.

Problems With Other Callers

If nothing else is wrong with your computer's sound and microphone settings, it is possible that the issue is on the other end. If you cannot hear another caller, use ooVoo's instant message service to ask the caller to check that her microphone is plugged in and that her ooVoo settings are accurate. If the caller cannot hear you, ask her to check that her ooVoo and Windows sound settings are accurate.