Ethernet doesn't have IP configuration

Last week we got the new xfi gateway modem and installed it. Everything worked fine that day, however the next day the desktop computer would not work, but all of the other devices could connect to the xfi gateway.

The error message for the desktop computer said ""ethernet" doesn't have a valid IP configuration."

We restarted the modem, made sure that all the plugs were tightened/inserted correctly, unplugged and plugged everything back in, called customer service but would be told in the end to talk to the original manufacturer for the tower, we took the tower in to be serviced but was told it was working fine with their internet.

Would anyone happen to have a solution for this problem?