Another two days, and still no joy on Windows.
I just read HERE, however, that installation of Apple Bonjour is recommended as a way to help the raspberry Pi getting an IP, when connecting it via direct ethernet cable on Windows...I don't really remember if I have already installed Bonjour or not...I will check tonight, anyway, and see if installing/reinstalling it does the trick.
I'm still open to suggestions, eh...don't be a stranger, if you know something I might have missed. ;)