try turning off SSID Broadcast. This prevents anonymous users from detecting that you have a wireless connection present."
And it makes it harder to use your network. And it prevents non-anonymous users from detecting your network. And it prevents neighbors from detecting channel conflicts, which might prompt them to change channels to avoid interference. And it does not deter the bad guys from using your network. For security use WPA encryption (after you get your network working satisfactorily) and forget the other junk.instanthelp