to reset/restart your router and/or modem? Oftentimes the problem is at that point, rather than with Airport. You can log in into the router using any browser and typing the address written on the router or its manual. Normally, the connection status will be displayed by the router. Restarting your ADSL or cable modem may also be needed. Hope this helps
It detects my wireless and connects to it, but the status shows 'not connected' and I cant access the internet. Network diagnostics is of no help. What do I do?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic