Booting from USB works, you can even boot WinXP from USB, or even install your OS on your rams and let it boot from there, I also have a Windows XP Live Cd made by a french guy that boots from CD just like Knoppix does.
A friend of mine installed his WinXP on his 2GB ECC rams and is booting, and working from the rams directly.
Samer, Ozzi, you can't assign your BIOS to boot from USB, unless its there in newer boards. (I still work on my lovely P3 1ghz), but i doubt it.
7aRami, copying files won't do shit. in every devices there are boot sectors that you can't see or modify that easy, especialy in Windows, you can do that using IsoBuster to extract the .boot file and modify it..
just go to
http://www.google.com/linux, you'll find all the help you want there.
another thought, if you don't know how to use some advanced commands of linux and understand them, you won't know how to deal with it.
