With the greaatest respect, Asha86x said this laptop connected when connected by cable to another laptop - presumably ethernet.
Could it be that the wi-fi unit in the laptop has died, or at least failed in one direction ? This gave me no end of problems once when I was trying to set up an ad-hoc connection between my wife's old laptop and my desktop unit. At the time I knew rock-all about wireless networks, and it was only after I had installed a router access point I established what the problem with my wife's laptop was.
The solution was to install a wireless USB adapter on the laptop. Instant success.