Your search for "ISO bootable" might lead you to a problem: You have the ISO, but your target machine has no CD drive. Booting XPe from USB is notoriously difficult because Windows XP does not natively boot from USB.
But for enthusiasts, retro-gamers, and IT professionals maintaining legacy hardware, the holy grail is creating a drive. This article is your comprehensive guide: what it is, why you need it, how to create it legally, and advanced troubleshooting tips.
installation media, which contains the tools to build the OS, rather than the OS itself.
You cannot simply download a “Windows XP Embedded ISO” from Microsoft today (legal channels require an MSDN subscription or legacy OEM agreement). However, you can build one using the Windows Embedded Studio 2006 toolkit.