Thanks for replying, but...
I still won't click on a button when I don't know what it does, ie what software is not updated, what entry is uncorrect etc...
If Avast doesn't show me what it can do before I click on that button, then I'll just uninstall it, end of the experience, and going to find another AV.
But still thanks for your replies, even if captcha is really hard to understand