Steam voice chat is not working [closed]

My friend has been with me and my other friends on Steam for a while. We would always hang out and talk with each other. But one day, his Steam group chat and VC stopped working. We went through the normal troubleshooting, but to no avail. He can enter the group chat, but it never registers as being "active". In his own words "I can enter the group chat, but when I try to use the voice chat, nothing happens."

He tried another Mic on the same computer, and it did not work with Steam. He used the same Mic on Skype, and it works perfectly fine. He used the same Mic on a different computer , and it worked properly. Recently, he did a factory default on his computer, and re-installed Steam. this did not fix the problem.