Can no longer connect to a wireless network I was previously able to

Ok, I spend a lot of time over at a friend's house, with roughly 3-4 computers running on the same network. My laptop was able to connect smoothly with no problems for about a month. One day another friend came over and connected his laptop to the network, before mine was connected, and since then I have been unable to connect back to the network even after he's left with his laptop long gone. I've tried restarting the router, tried to release/renew my IP with the cmd prompt (however was only displayed "media disconnected" for all my connections), tried setting a static IP, and none have given me any results. My laptop recognizes the network with 4-5 bars, however when trying to connect I'm simply given a message saying, "Windows was unable to connect to (network name)". I have no problem connecting to my wireless network at home, but for some reason am unable to connect to my friends. I'm using a Dell Inspiron N5110, along with Windows 7. Any help would be appreciated.

Can you display your Ipconfig /all in the command line and Post it here.

ipconfig /all > network.txt & network.txt

will out put it to notepad.