After extensive Googling, I need to take a break, and find out if someone with more experience knows what I can try next... I'm not the best when it comes to Networks, or even router configuration. I'll just put that out there, in case I've missed something obvious. My router connection (DLink 2640B) was working perfectly fine before I upgraded to Snow Leopard. Now I cannot connect to any wireless network, and I cannot connect to the router administration page, either (192.168.1.1). The internet connection still works fine on two other laptops. Also, I can connect this iMac via the ethernet cable. I've tried deleting the files NetworkInterfaces.plist, com.apple.network.identification.plist, and preferences.plist; I've tried rebooting my router; I've tried creating a new network. Airport sees all the networks, tries to connect, then it just says that it fails. If anyone has any advice, I would be so so happy. Thanks so much.