what its mean when I click on wi fi icon its shows notification "no hardware installed"

As the wifi connection in my workplace was down and being fixed, I recently use the ethernet connection. Therefore I turn off the wi fi air port base system on my MacBook Pro. For abut two weeks I keep using the ethernet to connect to the web. On some occasion I take my mac along to other place and try to connect to the web with wi fi connection. Its take long time trying to connect and finally its fail. After that when I click on the wi fi icon it show a notification "no hardware installed" instead of searching for air port base. Unfortunetly when I trying to use the apple hardware test, I colud not find it on my mac.