I know it may sound lame but have u reset the router? Have you reset the network adapter on the pc? if its windows seven its simple. Have u tried removing the computer from the network then erasing its credentials to that network then reconnecting it and setting up new access credentials for that pc? Essentially allowing ur computer to be recognized as a new pc on the network and restablishing its rights. Tech babble... lol Also, if you are using wep try using a different access key provided by your router. Good luck.