My uncle has an Aluminum iMac. He called me earlier in the evening saying he couldn't get online. He's connected via ethernet. We reset everything and I had my dad over his house with his macbook air. My dad was on wireless no problem and the internet was fine. I told my dad to bring up safari and iChat and we connected on his iMac. I used screen sharing and brought up network utility. When I pulled up EN0 for ethernet, the hardware address would flicker between the MAC address and "Not Available" every min and a half or so. So I'm thinking bad NIC? I switched to FW1 (firewire network adapter) and it would do the same thing which threw a wrench in the works.... Something screwed up in software? I plan on doing a time machine backup and installing Leopard from scratch. I was over his house last weekend and did the firmware update available for it but this is the first he had a problem with it. Also, not once during the remote session/video chat did the internet connection drop even with it switching back and forth. So, needless to say I'm stumped.