The hard drive you wish to format must be the only drive in a computer with windows loaded on it.
If you have a floppy drive and are running win 95/98/98se. Then download a dos boot disk from click here. Pick the 98se one. Download it to the desktop and place a blank floppy disk into the drive. Click on the download and it will write to the floppy disk.
restart the computer with the floppy left in the drive. It should start to load.
pick the option to start with cdrom support.
It should load to a:\ prompt
type format c: after this, check the spaces, so it looks like this
a:\ format c:
and press enter
it will ask for a label ( name ) if it has none just press enter. If the drive has a name e.g. anniesboy68 hard drive, type that name for the label.
it should ask if you are sure
press y for yes and it will format the hard drive.