I have one of the first MacMini that were made and I am trying to install Snow Leopard.

I am trying to install Snow Leopard on to the Mac Mini that I bought not long ago, it is one of the first Mac mini made, I was able to get the Mac mini and mini win7 drives to erase but am having no luck at all to get the 500.11 gb wdc wd5000bevt-00zato media drive to erase. anyone willing to suggest any idea in helping me out.