Installing windows off of a USB stick

I have googled this and I seriously can't find any good guides. None of them make sense.. I have the HP formatting tool and I formatted my flash drive for FAT and I put the ISO on it and it doesn't boot from it.. I'm trying to do this with XP and it just doesn't work.. Any help would be awesome.

I do it all the time so i dont have to plug a dvd drive into older computers/servers.

Copy the contents of the install disc (xp/vista/w.e) int a folder on the flash drive, Boot the machine from Vista PE (barts PE might work also) then run the installer off the flash drive from inside the live disc and away you go.

Check this and see if it helps:http://forums.techpowerup.com/showthread.php?t=83475

Step By Step from vista:
From admin cmd prompt

1. diskpart
1a. list disk
2. select disk 1 (replace 1 with your usb drive)
3. clean
4. create partition primary
5. select partition 1 (replace 1 with your usb drive)
6. active
7. format fs=fat32
8. assign
9. exit

Copy Windows Vista's DVD ROM content to the Flash Drive

xcopy d:\*.* /s/e/f e:\ (d being your vista cd and e being your usb stick)

And that's it, boot off your usb disk

http://myeeeguides.wordpress.com/2008/11/15/winsetupfromusb-install-windows-xp-from-usb-flash-drive/

This works for me- winsetupfromusb : http://www.msfn.org/board/index.php?showtopic=120444
Just click on the link for version 1.1. It installs a little app that does pretty much all of it for you. Just make sure to have source files ready to go. Should work with any newer windows, I used it to install xp64 on my server. Works great!