John, I use a Slingbox (same "ethernet > box thingy > power outlet" concept) from my router to my PC upstairs and have no issues streaming movies from it to my Xbox downstairs. I'm not saying you should buy a Slingbox, I'm saying lack of bandwidth is likely to not be the issue, but still could be. Can you draw a topographical map of your network in mspaint or something? That would help a bit.. probably be entertaining too.