go to : http://www.pendrivelinux.com/boot-iso-from-usb-flash-drive/
and download bootmyiso program.
This will make ur usb stick become bootable !
Open it then,select your usb key (E:\...K:\, dont make
mistake)Let him format your usb stick.
Then copy bios files on the usb stick. Boot on usb (F11 at startup) then
select FreeDos. Wait few secs. On c:\prompt type
Wait. When you finally see the success message, it"s all right !restart with
thanks david from france for this solution!!!!