Have you tried power cycling the modem and router? Just unplug the power adapter for about a minute, plug the modem in first, wait about a minute for the lights to become solid, plug in the router, wait for the self checking as leds flash, then reboot your pc and see if you can connect. Next step would be to use the Repair feature on the Network Connection. Control Panel>Network Connections>right click the connection and select repair. Another option is to try the Winsock Fix.
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