You should NEVER reuse your passwords for anything again, and I hope you learned a lesson about that.
Use some password manager like KeyPass for storing and generating new strong password for each website.
I had found some virus when I used windows defender to scan my computer some months ago.
Switching to Linux may also be a good idea so you won't need to use any antiviruses, and offline computer is much better for dealing with crypto.
Good ideas. I will try to do that now.