Have to run network diagnostics everytime to connect to wi-fi

I just started having the exact same problem. My ipod connects fine, but my macbook pro will not connect when I open the lid. Have to use diagnostics and re-enter password to get connected. Would love to see an answer to this.

At first my wireless worked just peachy. Recently, I was having the same problem as you, but on an intermittent basis. Now, I can detect my router, and I have good signal strength, but it won't connect to the internet at all! Restarting doesn't help. Meanwhile the wifi on my iMac works just fine.
There are tons of posts on these forums describing this same issue. Seems like there is a big problem with wifi in the new MBP's.
When will I learn my lesson and stop buying the first generation products from Apple?

I have just recently started having the same problem as you. All of my other wireless devices (wii, ipod touch 1st gen) connect flawlessly. This means it cannot be the router.

Just the macbook wants to set up the airport connection (WEP and everything) everytime I start (and also in each and every different account).
My router is a Fritzbox 7050 WLAN FON. Infuriating problem. please let me know if you solve the problem... could it have anything to do with the 10.4.6. update that i recently carried out? The laptop never had this problem before; it has been working with this router and connection for more than 2 years now with no problems.

I've had the Macbook 2ghz 13'' for nearly 2 years with no problems on the airport home network. In the last several months I started having dropped network. Network Diagnostics showed good connection no problems. Restart wouldn't help. Unplug and replug power to Airport would work until next time it dropped. My wife just got new Macbook Pro. Sometimes the drop happens to me sometimes to her while the other of us is still connected fine. Diagnostics says no problems. This is just to weird!

I found the solution after many many many attemps.

It's not a MBP problem, it's your wireless router.

1- Set your BEACON between 20 and 50. D-LINK router for example use 100 has default value. It's too long.
2- Change your channel. D-link default is 6. Use whatever channel. I use 10.

Hope you enjoy!

i would call netgear cuz mine works fine

have you tried to unplug and replug the modem and wifi router?