I suspect a virus in the antivirus, the usual treatment does not help?

Question

Malware

Win7 system, antivirus free.
unexpectedly, this very free antivirus starts blocking access to the Internet (to any site), if you turn it off everything works fine.
the program does not allow itself to be demolished, a one-time Dr. Web said about damage to the hosts file, when trying to “cure” it in the usual way (editing in notepad), it does not allow opening the file, it also does not allow copying the hosts file from an uninfected computer.
This free antivirus itself goes crazy when it starts checking and gives out all the files of the installed software as infected.
What can be done to cure the problem with minimal losses? It is impossible to format and re-install everything, there are gigantic volumes of working and valuable information on the hard drive (photo)
PS: I ask you not to speak in the spirit of “you need to install normal antiviruses”, you need a specific solution to the problem.

Answer 1

Cure data by
1. inserting the disk into a known healthy system with a normal antivirus (for example, utilities like drweb cureit or kaspersky removal tool)
2. downloading and booting from a livecd with an antivirus (for example, drweb livecd from an off site)

Answer 2

habrahabr.ru/blogs/infosecurity/117280/

Answer 3

like that's what happened.
110411-2 was quickly updated on top of version 110411-1 - and life seemed to get better. still testing...

Answer 4

the same oil painting. avast. went berserk half an hour or an hour ago and intends to delete absolutely all files.
all this after an automatic update session.
still hoping it's a bug in the update;
two different cars, not combined into a grid; after updating avast SIMULTANEOUSLY began to block everything.

Answer 5

If you really have some kind of bug in the system, then I advise: spybot.net A
quality removal tool that has proven its reliability.

Answer 6

When I eat sand, my teeth hurt. What to do? Just do not advise eating anything more edible!