This is because you are not booting up off of the CD or bootable USB key with the 1.8.0 restore image contained on it. Go into the BIOS and change the boot priorities to have either of those two devices boot prior to the internal hard drive.
Once completed, you will see the prompt - BOOT FROM CD. then Press any key to boot from cd. I typically just keep hitting a key on an external keyboard until it boots from the CD. you will hear it spin up and start reading from it.
As Ryan said you are not booting off the media, you are getting into the systems internal restore options. When booting the desk hit F8 on an external keyboard until you see the boot options menu. Choose the USB stick or your usb cd drive.