From XP HELP:
To format a disk
[[If the disk you want to format is a floppy disk, insert it into its drive.
Open My Computer, and then click the disk you want to format.
On the File menu, point to the name of the floppy drive, and then click
Format.
Specify the following options:
Capacity
File system
Allocation unit size
Volume label
Quick Format
Create an MS-DOS startup disk
Click Start.
Important
Formatting a disk erases all information on that disk.
Notes
To open My Computer, double-click the My Computer icon on the desktop.
Quick Format removes files from the disk without scanning the disk for bad
sectors. Use this option only if the disk has been previously formatted, and
you are sure the disk is not damaged. For information about any of the
options, click the question mark in the upper-right corner of the Format
dialog box, and then click the option.
You cannot format a disk if files are open on the disk, the contents of the
disk are displayed, or the disk contains the system or boot partition.
You can also format a disk by using Disk Management. For more information,
click Related Topics. ]]
To format a disk
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/win_format.mspx