Originally Posted by Hartmann

I've had this issue before. Try killing the wireless and restarting it, sometimes that forces a new IP to be handed out, sometimes it doesn't.

The rogue DHCP server idea makes sense, as I've picked up strange DHCP servers in the PC before, I'm guessing people who do not know how to configure their wireless settings have screwed something up. (I highly doubt there are phishers in the PC, but I could be wrong)