Let me make this COMPLICATED issue as clear as I possibly can: 1. I am using my brand new iMac with a Linksys AT&T router. Have been fine with my internet for months. 2. Today I tried connecting my Airport Extreme Base Station (old model from 2002) to my Linksys router 3. At the installation process in Airport Utility, I selected to "replace my existing network with my airport" (I think this was my mistake here) 4. Things started looking funny fast, I lost my Linksys connection and also my Airport connection - no internet 5. I immediately unplugged the AEBS and reset my Linksys router, ditching the whole AEBS 6. THE MAIN PROBLEM: My husband's SONY Vaio and my Macbook Pro both can still connect to our Linksys wireless signal, but my iMac CANNOT CONNECT (This is the computer I completed the set up of my Airport Utility with the AEBS originally) The computer says that "airport has the self-assigned ip address and will not be able to connect to the internet" However, I can connect to the internet on EVERY OTHER computer in my network except one: the computer I originally installed the AEBS on. 7. I have tried everything (and read all the forums!) including: -Verified that we are configuring the IPv4 using DCHP -Configuring the IPv6 automatically - Then I tried assigning a manual IP address within the range that my router owns and specifies also tried this (per another forum): 1. Go to Mac/Library/Preferences/SystemConﬁguration 2. Delete the following: a. Com.apple.airport.prefrences.plist b. NetworkInterfaces.plist c. Preferences.plist 3.Shut down computer 4.reset PRAM NOTHING HAS WORKED. How can I get my iMac to claim the proper IP address? I am absolutely baffled at this, and I am a very proficient tech. I have never seen anything like this before. PLEASE HELP! What is going ON???