Internet connection ruins Homegroup activity.

So I have 5 computers on a homegroup and they are allowed to access each other. Now I have another computer that isnt connected to the homegroup. Whenever I connect that computer to the internet via wireless or ethernet, one of the other computers on the network cannot access any of the computers on the homegroup, and vice versa.

All of the computers are connected to the internet by wireless and cable. But for some reason when i put this ONE computer on the internet, another computer that IS connected to the homegroup cannot be accessed nor can it access any of the other computers via network/home group.

Any chance it is a duplicate IP issue.

or even a duplicate NetBIOS name.

How would i change the netbios name?

I figured it out, it ended up having the same netBIOS as another computer. Thanks everyone!