Internet not working after installing snow leopard

Hello, I just installed snow leopard from tiger, and now I can't connect to the internet. On network preferences it says "Airport 2 has the self-assigned IP address 169.XXX.XX.XXX and will not be able to connect to the internet". I looked online and it seems like I have a problem similar to this: How I fixed my dropping wireless Airport connection problem in Snow Leopard

I had a guy come over to see if he could fix it, and he had the internet working briefly, but after I put it in sleep mode and came back 20 minutes later the internet stopped working again. I can pick up signals from my neighbors wifi, but not my own. Is anyone familiar with this problem?

Right now the internet is working, but should I assume this isn't permanent?

Depending on your equipment and provider sometimes a simple reboot of both the modem and router at the same time or as close to it as you can get will rectify issues.

Modem and router? As far as I know I just have a neatgear router which I've restarted before and it didn't do anything. Is that what you meant by reboot?

Set your network location to Automatic. Then restart your router and your Mac