MacBook Air won't connect to wifi networks
I have had my MacBook Air for over a year and have never had a problem connecting to the network (resetting the router or MacBook always fixed it). Howev today it has refused to connect. It is not my network as other devices are working on it and I also couldn't connect to my university network earlier today. The MacBook can find networks but is unable to connect to to them, can anyone help?
MacBook Air (13-inch Mid 2011), Mac OS X (10.7.5)