Is your router broadcasting it's SSID ? Can any other laptops find it ? Can you connect by cable ?
Try changing channel in the router in case you have a high power signal from another router swamping your transmission .
To find out what channels are being used by nearby router open a command prompt ( start/run , type in CMD and press enter ) then type in to the black box without quote marks " netsh " , press enter , then type in " wlan show network mode=bssid " , press enter again and you should get a list of nearby networks and their names and channel numbers , if any of them match yours and their strength is high change your channel number to something different .