Microsoft Windows 2000 and Windows XP recovery console syntax

format [drive:] [/q] [/fs:file-system]

drive: Specifies the drive to format.
/q Performs a quick format.
/fs:file-system Specifies the file system to use (FAT, FAT32, or NTFS)

Examples
When using the format command, remember all information on the drive
you wish to format will be completely erased.
format a:
Would erase all the contents off a disk. Commonly used on a diskette that
has not been formatted or on a diskette you wish to erase.
format a: /q
Quickly erases all the contents of a floppy diskette. Commonly used to quickly erase all
information on the diskette.
format c:
This would erase all the contents of your C: hard disk drive. In other words,
unless you wish to erase all your computer's information, this command
should not be done unless you're planning to start over.