The Windows XP startup disk allows computers without a bootable CD-ROM to perform a new installation of the operating system. The Windows XP startup disk will automatically load the correct drivers to gain access to the CD-ROM drive and start a new installation of Setup. You cannot upgrade from a Windows XP startup disk.

Windows XP Home Edition startup disks will not work for Windows XP Professional installations and vice-versa.

Download Setup Disks: Windows XP Home | Windows XP Professional

source: Bink