If this is an oem machine contact the maker and ask about buying recovery media.
i need your help again with my computer. wont get passed 5% in the diagnostic tool - repairing drive and will reboot and goes into a loop. what to do? also, the HD i have now is a 500GB (5400 RPM) Serial ATA hard disk drive - i dont have a cd for the computer, if i got a new hard drive how to i load windows on?