Streaming media from PC

I just bought an Xbox 360 Elite. I wanted to stream media from my PC to my Xbox. I have Media Center on my PC.

But I have a modem that only has one ethernet cable so it either goes in the Xbox 360 or the PC, I think the PC and the Xbox 360 both need to be plugged in?

I just bought an Xbox 360 Elite. I wanted to stream media from my PC to my Xbox. I have Media Center on my PC.

But I have a modem that only has one ethernet cable so it either goes in the Xbox 360 or the PC, I think the PC and the Xbox 360 both need to be plugged in?

MoeAlza