wireless network suddenly disappears

I have a gateway Mx7515 laptop that I've used without wireless issues for nearly 3 yrs. Suddenly today it tells me it can't see any available networks . It works fine with a cable, but just will not see my home network. The only thing I've done concerning the network is add another computer (a desktop) to the network by adding a wireless card to it, it can see the local networks (and the neighbors too). I also added another desktop with a cable to our router, all is working well with the router and every computer (3 total) except the laptop.