I see... I thought of that too at first. It is because of the latest version of renpy I used. Windows defender also thinks it as virus but it is not. What I do is I turn windows defender off first. Anyway, did you extract it first? (Right click F4VisualNovel-1.0-win and click extract)?
Hello Naomi! I rebuild this using version 7.4.4. It is not confused as virus anymore. I hope it works. Try to download it again. ^_^ It is just a sample so it's really pretty short.