I've been running Avast free version for a long time. I've had zero issues up until last week. I attempted to record audio from a YouTube video with Audacity. The video played just fine several times and I rewinded part way by dragging the seeker back successfully several times. When I attempted to record it with Audacity the video would lock up as if the internet connection suddenly got slow. Inside the YouTube screen displayed an endless rotating circle and the words "if problem does not resolve restart your device". After several attempts I cleared cookies, restarted, tried it again. Same thing. Played fine. But, once I had Audacity open and ready to record it stalled and same message. Then I tried to play a regular mp3 that is saved on my computer via Windows Media Player and it would not play at all even when I was off line. Cleared, restarted and Windows Media Player works again.
The symptoms duplicated the next day.

Avast free will only do a quick scan. It pretends to do a full scan but the % timer always stays at Zero %.
Thinking Avast misse something, although I don't click on things that I don't trust, I was going to install MalwareBytes and attempt a full scan with that but I'm skeptical about trusting the download due to reading about hackers creating a pseudo Malwarebytes that downloads a virus.

So, can one of you post a good MalwareBytes link here or in a Private Message for me.

Or, do you have any other suggestions? All else seems to work fine but I have not done a full scan of any type for maybe a year or so.

Does the noise in your head bother me ?