I am trying to downgrade an HP Pavilion DV6000 from Vista Business 32-bit to XP Pro. I have an OEM XP Pro CD, but when I boot from the CD, I eventually get a message that says "Setup did not find any hard disk drives installed in your computer. Make sure any hard disk drives are powered on and properly connected to your computer, and that any disk-related hardware configuration is correct. This may involve running a manufacturer-supplied diagnostic or setup program. Setup cannot continue. To quit Setup, press F3."...........I am very confident that there is nothing wrong with the hard drive considering I can boot and install Vista using the System Restore DVDs. Any help would be greatly appreciated.