I have an IBM ThinkPad with a 30 Gig Color I-Pod, and I plug it directly into the computer and it makes the noise when you plug something in, but my I-pod doesn't show up under "My computer
or on I-Tunes!
Mine does that sometimes too. First make sure no one else is logged on with itunes open. Then reset your ipod by pressing and holding menu and select until you see the apple logo. That usually works for me.