Shut down and remove power from both med and router. Then turn on the router agsin....followed by the med.
If that dosn't work.....re-install the firmware (why not 4.0.5).
What was your prevous firmware? If v3 then you might have known dns issues identied when 4.0.4 was first released. There is a tip for dealing with that problem...but's a bit complex for this time of night.
http://www.mede8erforum.com/index.php/topic,4014.msg27109.html#msg27109