As soon as I start my MacBook (intel 1.83GHz White), there is a process "airport" that shows very high CPU usage (upto 99.9%). The MacBook gets hot, and soon the fan starts running at full speed.

I searched on the internet and have tried the following (but nothing worked):

1. Uninstall "vineserver" (VNC server) via AppDelete
2. Checked if internet sharing is enabled (disabled always)
3. Stopped iTunes sharing
4. Checked login items - no network related login items in my account AFAIK
5. Disabled Quicksilver autostart

More twist to the story: This happens only when I connect to my home network wirelessly (my router is 2wire). When I connect to my friends' networks (many of whom also have the same router), there is no such CPU-hogging process! Can someone please explain this?

After my MacBook started failing to sleep, this is the second major problem I am having.

Someone please help. The MacBook is one of my major investments in my education. I am willing to provide as many details as one could think of. Thanks!