I know there have been other MacBook wifi issues, but my situation seems to be a bit more unique...and I'm hoping someone has an idea of how to fix this... For the past few months I've been using my mid-2007 MacBook (running Snow Leopard) with a Samsung external TV/monitor (with the MacBook's lid closed). I had no problems whatsoever in terms of internet connection to my D-Link DIR-655 router. Yesterday for the first time since creating this setup, I took the MacBook with me somewhere. When I returned the MacBook to my network (closed lid, plugged my monitor back in), I started having wifi trouble. The wifi was initially running very slowly and then not at all. The wifi icon on the menu bar was showing regular strength, however. The complicating factor here is that when my MacBook is on, all other computers on the network show getting wifi signals but the connection isn't working for them either. When I turned off my MacBook and powered down/up the modem and router, other computers could connect successfully. (But when I turned my MacBook on, the computers lost connectivity to the internet.) What is causing this and what can I do? I've already played with the router's channels without success. I also made sure there weren't any unnecessary items in my Mac's DNS listing. This is driving me (and my roommate) crazy! Please help!