I am not really sure what caused it, or when it stopped working. But I noticed it a week ago, where the audio no longer gets carried out to the HDMI. There is however, one culprit that I have found which the (one of two) High Definition Audio Controller has an exclamation mark next to it, with a device code of: This device cannot start. (Code 10) What I have tried is reformatting my SP3, doing a full refresh/reinstall. But the exclamation still exists post install. I have also tried different TV's, which all work using another device over hdmi. Im not really sure where to look for SP3 drivers, any help would be appreciated!