Trouble connecting to wifi

Hello - my macbook pro (10.7.5) will not connect to my home wireless. It connects fine at my work and through other wifi connections. At home, it assigns an IP of 169.254.xx.xx to itself and won't connect (which I understand means it's not properly connecting to my modem). I have a macbook air (10.8.4) that connects to wifi at home with no problems. I have tried resetting my router, powering down both devices several times, resetting the DHCP... nothing works. I've even tried forcing it with manual assigned DHCP. The macbook pro connects at home when I plug it into ethernet. The modem is a Motorola Netopia, model #3347-02. Any ideas?

G'day and welcome to the forums.

Perhaps a failed Airport card. What does Apple System Profiler (about this Mac) say about the card?

Turns out the router's settings were on WEP security. Once changed to WPA2, it was corrected. I have no idea why that made the difference.

I can answer that one. Apple no longer supports WEP at all because it is the same as having no security, it is so easily cracked. Congrats to you for figuring out the problem yourself!

That use to be one of the first suggestions we made a few years ago. This has been an issue with WEP and Macs since about '07. I've gotten to the point of thinking everyone has changed to WPA2 by now and forget about it.

Back to top of the list it goes, especially when we see issues of connecting only in one location like this.
And thanks for reporting back your fix - we appreciate that.

@ OP Kudos for figuring that out so quickly. Never even crossed my mind as a possible source of the problem. It should have though. I had the same problem as the OP a few years ago when Apple first made the change. Drove me nuts for a few weeks trying to figure out the fix.