Ok, so I've finally managed to install Windows XP on a Dell Studio 1537 Laptop without a DVD or CD drive (it is broken and lappy is out of warranty). It was a heck of a time trying to install Windows XP from a USB Flash Drive, but after a few days I finally got it. If you're wondering how to do the same thing, I followed the instructions here:

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

I used a slip streamed Windows XP SP3 with SATA drivers.

It wasn't working until I watched this video a second time: