It has been a while since I did it, but unless you can find the password you will need to rebuild the gateway. I am assuming this is the Gateway Appliance not the old ISO image on your own hardware.
It only takes under 1/2 hour to build, you will need to work at the device itself, upon rebooting it you should see some options, I forget what they are, but it should be clear, choose the rebuild one.
Thanks! I see the option to restore factory defaults. It won't take long to reconfigure the dual nic setup again. Thanks again!