Desperately need help. All of a sudden, my wireless system shut down. I cannot log on using airport because I get an error messages saying my IP address is being used by another computer on the network. I use a Verizon DSL modem into the airport extreme to work my network. I have two Macbook Pros and an iMac desktop. We also have a couple of ipods and wireless Directv. I had no problems for a couple years and all of a sudden, my network is shut down. I turn everything off except the iMac and still the error message. I have tried inputting manual IP addresses on my imac and turning off both laptops. Every time I put a new address in on any of the computers and try to apply it, an error message comes up and says another computer is using that address. This SUCKS! Please help!