Formatting of a hard drive is necessary if the computer does not start, the hard drive is full, viruses exist in the system, or the hard drive needs to be updated. Computer users also choose to format a hard drive if the computer is running slow.

Format hard drives if the computer displays black screens, registry errors or virus pop-ups to eliminate barriers that impact the speed and performance of the system. Reformat a hard drive that is too full when space is slowing down the system. Hard drives that are cluttered with downloads, large memory programs, and extensive data and files often require formatting. Reformatting is also necessary when users do not perform routine computer maintenance and disk cleaning, resulting in slow system performance or startup failures.

Reformatting is also necessary when individuals are running Windows on their computer and need to reinstall the operating system when it is not running correctly or needs updating. Formatting a hard drive involves deleting all data present on the computer as well as the software and applications. Users must reinstall software applications once the hard drive format is complete.

Users should back up computer files and data that need to be retained on an external hard drive or flash drive before reformatting a hard drive.