Mediasonic Mediaplayer HM2-SU2TV Not Working

I bought a media player for my family for Christmas this year, this was they can watch any videos that we have on our computer, on our TV. This may have been a good idea if it had worked. The model number is: HM2-SU2TV, i have a link of the exact media player I have at the bottom. I bought a SATAII hard drive, like the box said I need and the guy at the place where i bought it, confirmed i needed. Plugged it in the media player and then into my computer but the computer doesn't even recognize that there is anything plugged in. Help?

http://www.overstock.com/Electronics…6/product.html

I don't know the hardware mentioned, but the usual reason for a hard drive not being seen by the system is down to it needs formating before it will acknowledge it's there, I suspect this is the case here.