mac wont connect to home network

Just lost internet connectivity. When I try to connect get connection timeout. I used network diagnostics and it seems the password is no longer in the keychain when I enter the password it tells me that network configuration has changed, press OK to continue then I get the message that connection has failed either I am out of range of the router, I have entered the wrong password or whatever.... on the actual connections bar on the left it has no IP address beneath the wifi indicator? I am making this post on another computer connected to same home network running windows8 so network is not the issue, just the mac.