Skype Randomly Mutes Microphone

[Petie]

Malware is often the cause from what I've seen. Like I said earlier, run a full scan with Malwarebytes (https://www.malwarebytes.org) and, if you're still having problems after that, ComboFix (http://www.bleepingcomputer.com/download/combofix/, though I'd be careful with this one - it's very powerful but also potentially dangerous if you're not sure what you're doing).