Windows 7 - Win7 Local area connection doesn't have valid ip configuration

As the title says, that is the name of problem that the Network and Sharing Center says on Windows 7. A person on my Superuser question says that it is because my DHCP is disable and I have had no luck enabling it. I have unplugged the modem and router, I have reset the router, I have setup OpenDNS on my router, I have tried three different ethernet cables that all work fine. You can also see my Lockergnome question for other things I have tried. I have read other posts about this problem on other threads but none of the solutions have worked for me. Any help is greatly appreciated. Thanks.