In reference to "refurbished" XBoxes from EB in particular:
I went through three, yes, three "refurbished" XBoxes from EB until I got pissed off, gave them the finger, and bought a new one because the extra money was worth not having to go through the hassle of another beaten to hell, faulty POS they like to call "refurbished."
Good luck if you buy a used one, you'll need it - from what I've gone through.
... and don't accept a Thompson Drive XBox no matter what. Those things are practically cursed.