I have a 2 month old MBP. After about one month of happily using the wireless network, it suddenly stopped working. I couldn't figure out what had happened, but had to go to work, so left it. The next morning, the wireless was fine. Another 3 weeks go by, and it happens again. One minute, all good, and the next time I log in, no go. The signal is there, I am asked if I want to join the network, and when I click yes, I get the "there was an error joining the XXXX network" message. My friend downstairs (we both use the same router) also has a MBP. Her airport was fine. I double checked all settings, repaired permissions etc. Nothing. I went into a Mac shop to see if I could connect to their airport. Nothing. The IT guy at worked tried to get the airport to work with his MBP. Still nothing. Reset PMU and PRAM and had no luck.I eventually resorted to using a D-Link wireless USB adaptor, which worked fine. I was about to go to the Apple Shop to try a new Airport card, but thought I would just give it a try this morning - 8 days after it stopped - and IT WORKED. Has anyone else had this happen. Any ideas about how I can prevent it happening again? Thanks.
