If you disable the adapter that is this 2nd connection it should no longer be a problem.
***The biggest problem for losing internet would be if both connections had a gateway configuration. If the 2nd was not used and set up as a static IP for say 130.0.0.1 and subnet of 255.255.255.0 and gateway is left blank, all outbound communications would have to go through the single gateway at the primary NIC and the problem is solved.
However you should be able to simply disable the 2nd network adapter and then force the system to communicate through the primary adapter.
To disable go to Control Panel, then select Network & Sharing Center, then select change adapter settings, then select the NIC that you want to disable and right-click and select to disable it from the drop down.
You then will want to refresh your network info. To do this pull up command prompt and type ipconfig/release and then after that brings you back to the prompt enter ipconfig/renew and when brought back to the prompt you should be able to ping
www.google.com and get a healthy response if the internet is available.
** Also on a rare occasion you may need to flush out the DNS info, to do this from the command prompt enter ipconfig/flushdns and wait for it to complete and then try to ping google again at PING
www.google.com If you dont want to go through the command prompt instructions above you can simply reboot the computer and it will detect the network info on the fly on start up of Windows and get a IP lease from DHCP from router etc, and you should have internet if internet is available.
