Updated to 10.6.6 - Airport No Longer Works

Question

I have a Black Macbook from about 2-3 years ago. It's been great throughout it's lifespan so far with hardly any errors and the errors I have encountered were always minimal and had quick fixes. That was until this recent update to 10.6.6.
Once I updated it, I could no longer connect wirelessly, anywhere. When I first select the airport drop down from the toolbar the first time I would see the local network/s and be able to select one. However right after selecting one it would give me a connection timeout and then the networks would completely disappear from the network selection area.
I hadn't really thought it was because of the update, I thought maybe I accidentally changed a setting or something around those lines. Well I have a friend that wants to buy my MacBook once I can upgrade (MBP). So I decided I'd just totally reset the MacBook back to the factory settings. I erased the Macintosh HD and installed Snow Leopard. Everything was perfectly fine and it was working just like new. So after moving over my music, movies and a few apps I decided I'd update it back to 10.6.6. Once I updated it, the Airport acted just as it did before (this is how I found out it was the update that screwed up the airport).
Are there any fixes? The furthest backup I have is from after the update (I had to get a new HDD because my other one crapped out). I have all my files, disks for apps, etc, etc so I'm not worried about manually moving / installing files, etc. I'm going to reset my MacBook back to factory settings tonight again and simply not update it. However if there are any fixes to this problem I'd greatly appreciate it, I don't want to be stuck in 10.6.5.

Answer 1

There are a lot of variables to a network problem.
There are also many threads of varying degrees of problems on here I've been reading over the past week about 10.6.6 having DHCP drops, slow speeds, all the way to this one, of no connection at all.
Everyone has the same solution, for sure...downgrade. If you want a 100% absolute (barring a hardware failure, of course), that is your answer.
Had you not downgraded, a guy in the UK went through just about every single troubleshooting thing I could think of/find in this thread here:
http://discussions.apple.com/thread.jspa?threadID=2710675
The only thing that finally worked for him was OnyX, which to me means it's a preference or cache file somewhere that they know about, and I didn't. Which is why I'm recommending running that in this thread first, before all of the other things I suggested he try.
Here is a link: http://www.apple.com/downloads/macosx/systemdiskutilities/onyx.html
It's free.
Message was edited by: lowfokus--poor wording, add link
Message was edited by: lowfokus