Boot Scan - 0 tested files and searched folders

Greetings.
The problem is as stated above - sheduled boot scan satarting, but quickly finishing with 0 tested files and searched folders.
OS is Windows 10, I am using Avast! Free Antivirus.
I have found exactly the same problem in forum search: https://forum.avast.com/index.php?topic=27577.msg224740#msg224740
But this is the case from 2007 year and Windows XP SP2. Problem was not solved, with conclusions, there is something wrong
with USB keyboard BIOS implementation. I am strongly suffering from virus that hiding from me in OS and without prompt
downloading and installing bunch of free crap with lot of ads. Every time I am chechking with processexplorer, autoruns, deleting unsigned
drivers, strange services, cleaning temp, programfiles programdata folders from trash, but no use, next day suddenly everything reappearing again.
Full scan in usual desktop mode gives me nothing.
Please help!

For help with malware removal > https://forum.avast.com/index.php?topic=53253.0