How to Erase a Hard Disk Without a CD
When you have a hard drive (either internal or external) with too much garbage taking up disk space, you may just want to start from scratch and erase all the data on the drive. Although you do need the Windows CD if you are reformatting the actual master drive with the operating system on it, there is no need to use a CD when erasing the data on slave drives (drives that do not contain the operating system).
Click "Start," followed by "(My) Computer," then right-click the hard drive icon. Make sure you are selecting the correct drive you want to erase data from. Once a drive is erased, you can not restore the previous information. Because of this, you need to back up your data before formatting the drive.
Select "Format" from the pull-down menu after right-clicking the hard drive. A new window appears on the screen.
Choose "Quick Format" and select "Format." A prompt appears asking if you are sure you want to format the drive.
Click "Yes" and all the contents currently stored on the drive will be erased.