I have seen this when Windows Security erroneously decided that one of the interpreters that drives the Story tab had a virus (it didn’t) and quarantined it. Check in the installation directory (usually C:\Program Files\Inform), there should be a folder “Interpreters”, containing “frotz.exe”, “glulxe.exe” and “git.exe”. If any of these is missing that would explain what you describe. In that case you might need to go into Windows Security (or whatever anti-virus you are using) and tell it to not quarantine the interpreter executable.