my motherboard is about a month old
Mine was less than two weeks, but the symptoms were not identical, so it may not be your MB. I was simply giving you a data point to consider in your troubleshooting.
Buzzing audio is a symptom that *can* be displayed by a bad motherboard. But mine wasn't freezing like yours.
It could be something as simple as a software issue, but it's too much of a coincidence that the symptoms appeared after a power issue, so I'm leaning toward hardware with the available info.