Router not giving ip adress properly

[TimiT]

Hello there

im having a problem here with my Macbook Pro 13".
i just completely emptied my hard drive and re-installed the Macos.
When i was visiting my girl friend, and was trying to re-connect to her Wi-fi, it connected, but it said "self-assigned ip" and "no internet-acces".
i then downloaded the updates through my Iphones shared internet connection.
Thereafter i installed Windows 7 Ultimate through boot camp(Because off the game in-compatibility with games and macs). I tried to connect to the internet here, it connected without troubles.
I am now using the windows boot camp to write this post.

Btw. my Iphone is connected to her Wi-fi, her pc is too.
my mac can connect to my Wi-fi at home, so as far as i see it must be the Router here.
I was connected to her network before the re-installation of the OS without problems
I have also checked if my Firewall was blocking me out, but found that it was disabled.
I have googled my problem, but could not find a working fix.

please ask if you need more information, and guide me how to get this information.

 

[satcomer]

What wireless frequency? Any router security like WEP or WPA? What version of OS X are you running?

 

[Plymouthbreezer]

What's your AirPort settings panel look like?

Config IPv4 should be set to "Using DHCP" and Configure to "Automatically."

 

[TimiT]

satcomer:

Wireless frequency?

WEP-security, i have double checked, and i have entered the right password.

i just updated totally so i quess my os is 10.6.7

Plymouthbreezer:
My Airport settings seems just like yours.

anyone ??