HDDs

I have a gorgeous new 400GB HDD. I [thought] I had hooked it up and the computer sees it in the system, hardware tab, but it isn't on my explorer.

Is anyone that's any good with hardware going to be available in the next few hours? I really wanna get this hooked up so that I can 1. move all my music and 2. fill it with FILEZ.

Thanks in advance!!