To format a computer hard drive, access the Disk Management screen via the Computer Management utility, select the desired drive, and choose the Format option. Specify a file system, set the allocation unit size, and use the desired formatting option. To format the primary hard drive that contains the system files, boot the computer using the Windows installation disc, and perform a fresh Windows installation. In both cases, back up personal files before formatting the hard drive.
Open the Control Panel, click on the Administrative Tools link, and double-click on the Computer Management icon. Select the Disk Management option in the Storage section, right-click on the hard drive you wish to format, and select Format. Choose a new designation for the drive by typing it in the Volume Label field, select the NTFS or FAT32 file system, and set the allocation unit size to the default value unless you want to customize it. Finally, select the Standard Format or Quick Format option, click OK to start the process, and wait until the Status message changes to Healthy.
For a primary hard drive, insert the Windows installation disc, and restart your computer. Press the appropriate key when the Select Boot Device or Change Boot Order option appears while the computer is booting up, and select the optical drive housing the installation disc as the primary boot device. Follow the instructions in the installation wizard, select the primary hard drive when prompted, and complete the installation process to format the drive.