Thanks Denther and Perkomate for answering. Do I need another computer, can't I format on the computer itself?
RoyT
I'd download Killdisk or Darik's boot and nuke (Dban), burn it to a disc and boot the disc and zero out the drive.
It is harder for an amateur to recover data from a zeroed out drive than a formatted one.
Recovering data from a formatted drive is too easy.