Vista - Do not want to Network, just want internet connection.

Hello,

I have three computers. one on the main floor (my wifes Vista) and two in the basement office (one win xp and one Linux).

We have a wireless router modem (from our internet service provider) and have my wifes computer connected to the modem. I ran CAt 6 cable from the modem to the basement where I have another wireless router. I configured the router to work by disableing UPNP and DNS (basically like a ethernet switch) Everything was fine.

Curious to see what windows 7 was like, I installed it on one my pc (the linux one). That was a big mistake. It tried to creat a network and see my wifes vista. Now my wifes Vista has lost the internet connection.

The only way the internet works on her vista, is if I unplug my ethernet cable from the modem and restart her computer. As soon as I plug my ethernet cable back in, it wants to connect to a network and she looses the Internet connection.

I don't want these computers communicating in ANY WAY. I just want internet in my office, and internet for my wife. I have recently formatted Windows 7 off my pc and installed Ubuntu back on.

Is there a way to configure the wireless router modem NOT to connect to a network? I just want it to provide internet for me and my wife, thats it.

Can I delete the network on the Vista and go back to how it was originally?

Any help would be appreciated.

Thanks in advance
John