Boot Windows XP from a usb drive...want to use OS on drive

[IamtherforeIthinkpad]

I want to run an Win XP directly on my flash drive.
I want to load my operating system on a 16G USB flash drive with multiple programs on it.
If I can boot on it, can I then load Win XP on it ?
Here is what I want to do.
I want to essentially have two computer systems that are run on one computer.
I have a company computer and I want to run my own files and programs all on one USB stick.
I have read that you can boot XP from a USB drive, but, I am not sure if this means that I can load the entire operating system on that stick.
Just need clarification ,
Thanks