Hello everyone, I was hoping that I could have some help with fixing a problem with an iMac. To give some background, it's a 27" 2010 iMac that just recently had a fresh install of OS X 10.6.4 which works fine until I get to the desktop and attempt to connect to WiFi. Here's what happens: I see that the airport has detected my WiFi connection and click it before entering the password to connect. The moment I click connect the iMac immediately freezes and suddenly the screen starts to dim/darken, starting from the top and going downwards until the entire screen has dimmed. Following this, a dialog box appears in the center of the screen in multiple languages, with the English text stating that I should press and hold down the power button to turn off the computer. I am able to replicate this problem 100% and as such, am unable to connect to the internet with this computer right now. This has never been a problem since the computer was purchased back in 2010, and I think I might know why? I'm not 100% sure however, and my attempt at remedying the problem has failed. The computer was kept up-to-date with software updates since purchase but since it was recently wiped and the disk that came with it was used to reinstall OS X (10.6.4) it is currently on an old version of OS X, which I suspect might be encountering a lot of trouble when trying to connect to my WiFi which uses IPv6? I have searched Google and seen other people encountering the same problem, so I assume it must be that, which would explain why it could connect to the WiFi perfectly fine before, since it was running a more recent version of OS X. I saw one proposed solution was to go into Network Settings and disable IPv6 for the Airport. I tried this and unfortunately it did not work, the computer still froze when attempting to connect to the WiFi so I'm feeling a bit stuck right now, and not 100% sure what to do. I have a feeling that if I could upgrade OS X somehow, it would fix the problem and enable internet access again, but I'm not sure how I would best go about doing that, or if there might perhaps be a simpler solution? I'm writing this post on a second computer that I have, but it's a PC running Windows 7. Thank you for reading, any help is much appreciated!