Maybe you don't have a CD-ROM or DVD-ROM, or you don't want to use one, or you are building a retro gaming PC and the onboard SATA controller is form VIA, and won't boot from an optical SATA drive. Easy2Boot is free and lets you put your Windows XP ISO images onto a USB flash drive and install it from there. It also has a driver pack for storage controllers and is all-round a great tool.
Site:Getintopc.app
Easy2Boot: http://www.easy2boot.com/
