Thanks for your help! This is what I did. First, because I panicked and I didn`t know what to do, I searched for some information on Google and this is what I saw Remove Windows Active Guard
. Indeed, there are some removal instructions here, but I preferred using Malwarebytes as you have recommended me to do and indeed it worked!
I run it in SafeMode ( I had it on a flash drive).
Now I can say that I`m a proudly owner of a fixed computer and I really hope my PC will not be infected again. Thanks!