Hi,
It seems the problem was the windows defender. Unquarantine files is not enough.
I've deleted the whole sdk folder, installed the tools again and started over with the antivirus offline. It worked.
I had some other errors; I've found you need to have hyper-v disabled too in order to the virtual machine to run.
I think this directions (hyper-v off, haxm installed) could be mentioned in the tutorial
here. That, also with "the command line tools must respect the folder structure and keep the "tool" as the root folder" could be obvious for experienced android developers but, for visual basic developers who are kind of new in android would be a huge time saver.
Thank you very much