Re: unable to contact your dhcp server.
Make sure your cable is connected securely on both ends. Unable to contact your DHCP server simply means that it's not able to communicate with the router. It could be a bad port on the router, something could have happened to the network cable, or the wrong drivers may be installed for the network card. Try to update the driver for your network card, and check all your connections. If after that, you still can't connect, something may be going on with your network card- they can go out anytime, just like any other component. Just to rule out the cable and the router, I would purchase a USB eithernet adapter, usually about 10 bucks or a little more. If your able to connect that way, bad network card, if not, corrupt OS possibly.
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