go to my computer, to find the drive letter of the hard drive. ie drive (E)
go to start, run, and type in cmd
a black DOS screen will appear.
from here you enter
format <drive letter (ie E)> "format e:" with out the " 's
it will say all data on this drive will be lost
do you wish to continue Y or N
hit Y, and the drive will be formatted.
Once complete it will ask for a drive name or press enter to continue.
Hope this helps