Is when folk install a firewall and set it to maximum protection. Try your scan again and take note of what it is finding. Browser hijacking is all too common and is not limited to Windows 10.
Also, this was a surprise:
This means I now run with just Defender and my 2 browser addins (Web Of Trust and Adblock+).
I bought a new Acer Aspire desktop about 6 weeks ago and immediately upgraded from Win 8.1 to 10. I have intermittent problems with accessing both Gmail and Facebook, often having to switch browsers, shut down all browsers and reopen, or reboot the computer. Even when I gain access it doesn't last for more than an hour or so before I start to have trouble following links, viewing pictures, etc. I have AVG (full version) installed and have checked Firewall options. I ran Malwarebytes once and that helped for a while (deletion of registry entries??) but then the problem recurred. Any suggestions?