Likely your PC has a SATA mass storage controller. Most BIOS have
a operational mode setting for the controller. If set to AHCI then XP
does not have the capability to see/use the controller and it's drives. It
requires changing the SATA to a "Legacy" mode.

"lengrass" <lengrass@discussions.microsoft.com> wrote in message
news:757FD7F6-9AA5-46C2-8A6D-769C8FD84F32@microsoft.com...
> The current OS is Vista Premium and I wish to install Win Xp Home. I have
> change the bios to boot from cd-dvd/hdd/disabled. Upon reboot and hit the
> 'enter key' Windows will do the setup. When asked to hit 'enter' to
> install
> the xp, I get a message that it cannot find the hdd. But the hdd is there
> as
> I can start Vista and do what ever I want. Vista in the pc is a complete
> working system, so there is no problem with the hdd.Any idea what is
> preventing the xp from been installed? Thanks for your help