I have a Hitachi 3TB Touro Desk Pro external hard drive plugged into my Windows 7 PC that does not show up on my computer panel. I've tried unplugging it, replugging it, several times but it still does not show. It did work fine at first and I could get into it no problem but it began to not show up on the computer storage device panel. Replugging it worked at first but now no matter what I try it does not show. Any help out there? Thank you.