I can connect to the internet through my pc but wireless through my airport extreme isnt working

Title pretty much explains it. I called my intertnet service provider and they told me because i can still connect through my pc it isnt the service but rather the router. Error messages from my airport extreme say i dont have a valid ip and i dont have any dns server addresses. No clue what triggered this, i was just browsing the internet last night and it randomly cut out, and wouldnt fix. I disconnected the router, modem, re configured the router, rebooted my computer, pretty much everything i could think of. I would appreciate some help. Thanks.