Fix for Airport Wireless Connection Problem stating Self-Assigned IP and not wanting to connect in Lion OSX.

Fix for Airport Wireless Connection Problem stating Self-Assigned IP and not wanting to connect in Lion OSX.

Bought my girlfriend the newest Macbook Pro 13" and began experiencing problems with my wifi the moment we got home. Her Macbook would not connect to our home Wi-Fi while my old Macbook Late 2008 running Snow Leopard connected without a problem. Airport would say that it had a Self-Assigned IP address (168.x.x.x). Did not realize it was a Lion problem until after using her Macbook Pro and becoming jealous of the new OSX, I upgraded. Soon after I was unable to go online. Luckily I had my iPad 2 and I began to scoure the net for help. Ran into allot of suggestions but it was not until I tried the following all together was I able to share the good new, from my Macbook. Hope this works:

First go to Preferences > Network and click on the cog next to the + and - on the sidebar and click Set Service Order

- Move Wi-Fi to the top and click ok.

- Set location to Automatic

- Click Apply

- Click Advanced

- Click the "-" on the selected Wi-Fi router you wish to connect to

- Click Apply

- Click Lock to Prevent Further Changes

Go to your Mac's harddrive, (Macintosh)

- Go to Library > Preferences > SystemConfiguration >

- Delete "com.apple.airport.preferences.plist" file

Turn off your computer

- push and hold Option+Command+R+P

- turn on computer

- when the grey screen turns on you will hear the OS X "ON" sound (for lack of a proper term) and it will momentarily restart.

- you will once again hear the "ON" sound, let go of all keys.

- this resets your PRAM

Go to Preferences > Network > Advanced > + sign

- click Choose a Network

- Select your network and enter password

Viola!!! I tried this on my Macbook Late 2008 and my girlfriends new Macbook Pro 2010