stuck on "please connect apple tv 2 via usb to computer"

I bought a tethered apple tv 2 5.2.1 from ebay. This was probably stupid of me.

I have right clicked create ipsw and selected 5.2.1, and also tried 5.3

I connect the apple tv to the computer and it just doesn't recognize the device is connected. The cord is working because itunes automatically starts itunes. I've tried this on two windows 7. My mac needs a motherboard, so I can't try it on there.

Any suggestions? I can only think something is wrong with the cord-so I'll get another one tomorrow if I can't solve it.

I'm not sure what write, or where to start.