Unable to get internet through my MBP when connected via Airport

[markwco]

I have a MacBook pro that I'm having issues with. It connects to my home Wi-Fi (the n version of the Apple Airport Base Station) and I get a strong signal but whether I use Firefox or any other web browser or internet based program I get a message that I'm not connected to the internet.
I can even select network diagnostics and it walks me through steps where I choose my network, reset my cable modem, base station, etc. and at the end it says it is unable to fix the problem.
i have a 2nd MBP that I use on the same network with no issues at all. This issue started showing up about a month ago but did not happen often. Most of the time it happened when I had shut my MBP down since I had to go take it with me to meetings. Often after removing the battery for a minute I could boot up and it would work but now no matter what I do it won't work.
Any ideas of what could be causing this? I know I may have to go to the genius bar to have this looked at but hope to avoid it. Is there any other troubleshooting I can do? Thanks for your help.

 

[Sur3Mac]

Maybe the two are using the same IP adress... try changing one of them in your networksettings.

 

[markwco]

Where would I go about changing the IP address? I tried using the MBP at a friend's house today and it didn't work on his wi-fi. Would this mean the IP address wouldn't be the issue?

 

[andr3wkim]

If you need to change the IP: just open System Preferences, select "Airport" on the left side pane, click on "Advanced...," go to TCP/IP and select "Using DHCP with manual address OR Manual".

Looking at your issues here, it seems more like a hardware issue. If you could kindly share screenshots of the "Advanced..." options of the Airport card on the MBP, maybe I could tell you if it would be easier going the Genius bar. Good luck!