how to boot from usb if my pc or laptop does not have the option?
-burn iso to cd
-boot from cd
-if you get message "Loading boot sector, waiting for any key to boot. N = continue search",
press enter to continue booting from usb.
If it does not work, try pressing u, or "shift u", or "ctrl shift u".
as seen here http://forum.plop.at/index.php/topic,34.msg709.html