everytime i reboot my MP, the Airport Extremem doesn't detect my wireless internet. it doesn't turn off, just shows grey bars. i get back on wireless internet by clicking on it and select the wireless name. first few times, ok. after a few times, gets rather annoying. i made sure i selected "By default, join: __my wireless network__" in System Preference -> Network. still no avail. i repair permissions, fsck, cron script regularly. any other possible cures?