New MacBook Pro won't connect to the internet while other computers will

On your router, are you using hex or english for passphrase? Also, what brand and model router?

I have 2 Linksys WRT54G routers. One that is version 2 of the router running the DD-WRT firmware, the other is version 6 of the router and has the stock firmware on it. The DD-WRT one is my main router with the other being a backup in case of emergencies. The I'm not sure what you mean about the passphrase but it is a combination of english letters and numbers.
I have had my MBP for 2 months and up until 10:30pm on Sept 29th it worked on the DD-WRT with WPA2 security just fine. All of the sudden it quit connecting. I made no changes to my wireless network whatsoever. The MBP would not connect to either router when any form of security was enabled but had no problems when security was disabled. It can see mine and other wireless networks in my neighborhood but cannot connect to any of them if security is enabled.

OK. Sometimes hex equivalents need to be used in order to connect with certain non-apple routers etc..
So you can't connect even with a WEP key of 00000000 or something?
Try zapping the pram, Boot holding the cmmd option+PR for 3 chimes and release.
Also ditch your network prefs and airport prefs.
Located here: /Library/System Configuration/com.apple.airport.preferences.plist
Maybe try to boot Safe mode as well. This stops certain daemons and 3rd party stuff from starting at boot. Try to connect under safe boot. Boot holding down the Shift key.

Hi peeps, I'm finally surfing from the comfort of my living room without my ethernet cable plugged into my Macbook!! Finally.....

Michelle, u r a life saver 🙂 Might I add also for all those who still cannot connect to try logging on to ur router set up page and under Channel and SSID (if that is what it says....mine's a Belkin) and change the Bandwidth to 20Megahertz to 20 + 40Megahertz. Bascially I tink the default is 20 but if u cant connect, it is worth a try to change it to the latter. Hope it helps!

Thanks u guys!

Ok guys, we had the same problem at work and since I can't play with the rooter, I had to find something else.

For me, Michel's solution wasn't working, I had to improvise a little bit. Qe have two macbook, one Macbook 13" 2.4 and one Macbook pro 13.3", both are on snow leopard.

Only the Macbook pro 13.3" had this issue and I tried everything and didn't get anywhere. So finally, I found something strange... On the Macbook 13.3", I had 4 protocol activated but on my macbook 13", I had only three ! I deativated the one that wasnt listed on my macbook 13" and tried again. Still no connection, BUT my PEAP certificated was valid. I was able to communicate with the server, but wasnt able to retreive an address IP !

After that, I opened the TCP/IP tab and tried to renew my bail, but that option wasnt even there ! Next, I tried to manually set an ip adress, I knew that it wouldnt work, but guess what, after trying to manually set it, I set it back to DHCP and my renew button was finally showing up ! So I pressed it and now all is working fine...

Hope it'll help you guys !

Have you seen all the other discussions reporting this problem. You can leave feedback for Apple here...

http://www.apple.com/feedback/macosx.html

Here is what I have just written to them...

Hi, I love my 13" MBP, I have had it for around 6 months now. However recently I have found that it randomly disconnects throughout the day. Extremely frustrating. My old Macbook nearly 2 years old I gave to my wife does not suffer from this at all. We both connect to the same router on the same network. I am not the only person finding this. At the time of writing this mail to you there are over 8000 views on one single support forum thread entitled "Wireless disconnects randomly throughout the day on 13" MBP". There are also many other forum threads describing the same fault. Infact 8 out of the first 15 discussions on your 1st page list of threads reference this problem- thats over half! All people reporting a problem with MacBook Pro's and wifi connection dropouts, running both 10.5 and 10.6. Please can you sort this out.

Here is a list of forums where people are begging for a solution. There are more discussions than this, this is just a selection. Please don't ignore us.

8411 views http://discussions.apple.com/thread.jspa?threadID=2116174&tstart=15

7912 views http://discussions.apple.com/thread.jspa?threadID=2108841&tstart=30

6029 views http://discussions.apple.com/thread.jspa?threadID=2077738&tstart=0

3180 views http://discussions.apple.com/thread.jspa?threadID=2159149&tstart=45

2222 views http://discussions.apple.com/thread.jspa?threadID=2143268&tstart=30

1271 views http://discussions.apple.com/thread.jspa?threadID=2196802&tstart=0

1092 views http://discussions.apple.com/thread.jspa?threadID=2172455&tstart=60

865 views http://discussions.apple.com/thread.jspa?threadID=2103370&tstart=60

561 views http://discussions.apple.com/thread.jspa?threadID=2168865&tstart=15

532 views http://discussions.apple.com/thread.jspa?threadID=2199231&tstart=0

425 views http://discussions.apple.com/thread.jspa?threadID=2217751&tstart=45

334 views http://discussions.apple.com/thread.jspa?threadID=2220528&tstart=15

216 views http://discussions.apple.com/thread.jspa?threadID=2230572&tstart=0

264 views http://discussions.apple.com/thread.jspa?threadID=2227801&tstart=0

121 views http://discussions.apple.com/thread.jspa?threadID=2232460&tstart=0

75 views http://discussions.apple.com/thread.jspa?threadID=2235250&tstart=0

72 views http://discussions.apple.com/thread.jspa?threadID=2228356&tstart=15

88 views http://discussions.apple.com/thread.jspa?threadID=2233304&tstart=0

80 views http://discussions.apple.com/thread.jspa?threadID=2230603&tstart=15

152 views http://discussions.apple.com/thread.jspa?threadID=2230645&tstart=15

165 views http://discussions.apple.com/thread.jspa?threadID=2229632&tstart=15

96 views http://discussions.apple.com/thread.jspa?threadID=2231890&tstart=15

Kind regards,
Mike.