I found recently that my wifi has ceased to work on my 2010 iMac desktop. All I get is an exclamation point on the Wifi icon at the top right of the screen. The wifi here has worked on this computer before. The wifi is functional on several devices at home. I reset the wireless modem, still did not work. I took the computer to the Genius bar where their wireless seemed to work fine. They returned my Network settings to the default factory settings. I had Hamachi on my computer, which apparently really messes with Wifi connection. I uninstalled it, but I failed to check the box saying to reset the Network settings. (whoops) I'm thinking that if I can reset my Network settings again, I might have some luck, but it being a 27" screen I don't want to drag my computer to the mall again. How can I do that? Additional information: Running Mountain Lion. ummm. can't think of anything else.