Wired (cat 5/6) No Internet Access on PC

Hey guys,

I've got a PC that I've connected to a secondary DD-WRT router via ethernet cable, I'm able to access the router interface for the primary and secondary router however I dont have internet access.

I've tried swapping the PC out for a laptop and have tried connecting it via ethernet and wifi and that works so it definately isn't the router, so i'm guessing someone has ruined the settings on the PC which means it doesnt have internet access any more.

Where do I begin to diagnose this problem?

I've tried disabling all of my firewall and security software, i've tried iconfig/renew on cmd.exe
The IPv4/6 is set to recive IP address automatically.
Running Windows 7, I've tried IE, firefox, opera, safari.

Any help would be much appreciated

Regards

Crazy

Has it ever worked in this configuration?
If so, try a system restore- usually works for me.

I managed to figure it out.

I did an ipconfig/all on both devices and the dns address was different on the PC.
Just manually entered the right one and voila

I'm a clever old boy when I put my mind to it you know

Cheers for looking fella