Windows 7: home location homegroup woes

Hi all ive been trying to set up a home network with the internet.
setting up the homegroup was easy for both of my computers, and getting the share to work is ok to. but when ever the network hub is connected to the internet only one of the computers can get online. So i tried to boot up both comps and had both of them set to public on the location and both connected fine but because i was not in home location could not connect to the homegroup, so set both computers to home location and again one computer has a connection and the other does not.
Both computers have windows 7 installed the one that connects all the time is home premium and the other is ultimate, both pc's have had the firewalls deactivated and they are both connecter to the network hub through lan cables.
I dont know what else to try and sort this out its been getting on my **** for a couple of weeks now and im finally getting to the point of admitting defeat hence why im here , any help or suggestions most welcome and i thank you in advance.

Welcome to SF,

Have you tried connecting both computers to the Router bypassing the Hub and see if you're able to replicate the issue?

If there's no issue there, it might be the Hub.

Another thing that you can do is try a diff Patch network cable, or plug the network cable to a diff Port in the Hub.
Unplugging the power plug from the Hub might also help.