input/output error

[Super20]

I have a 200gig hard drive that I pulled form a modded xbox. I bought a Mad Dog 3.5" USB enclosure to put it in. I plug it all in and my mac says that it's unrecognized and wants me to initialize it. Disc utilities won't do anything to it and says that there is an input/output error. It shows up in the window of selectable hard drives, but it doesn't mount. I've tried another USB enclosure with the same problem. Hard drives in xbox's must be locked to that machine. Could this be the problem and the drive needs to be unlocked to be usuable again or is this hard drive bricked? I would think that if it's bricked, it wouldn't be showing up as a selectable hard drive. It does say in it's info that it is unformatted. ANy ideas?