Press the "del" key at the post screen and go into the bios. Disable any settings related to the floppy. Set the cd (dvd) as first boot device, unless you're installing from a usb flash drive. Be sure your dvd cables are not loose, and check your sata connectors if required, since they can come loose easily on older non locking connectors. Also use only one hardrive at a time. You can add another drive later. Then try installing windows again.