Also I'd double check the Windows Firewall - try the instructions a user posted
here to fix a different issue caused by Windows Firewall blocking it.
Jim/Matt, this might be a good feature to add to MC27, a feature with a button that when pressed tests the downloading of components and gives the user an error message saying it's blocked by a firewall if it fails. It could be useful when troubleshooting issues like this. Also having 1) a download progress bar for components and 2) some sort of message when downloading components fails might be useful too, as it could help users in diagnosing and fixing connection/firewall issues on their own instead of posting on the forums for support.
I guess when I do the new version of the taming Windows Defender tutorial I should also do a second one for the Windows Firewall?