problem with my Dell Wireless 1390 WLAN MiniCard

hi everyone, i just bought my laptop insprion 1150, i tried to connect to the wirless network of the library and the wirless network of my work but in the list of networks there is no network availble, when i go to the network utility -> monitor  

i see that there is the network signal ( of the library or my work network), but in the list of networks still nothing

please help me it make me crazy :)