Vista Home Premium Upgrade from XP Pro

> I have a partitioned drive (minimal C, XP Pro on D, Applications on E, Data
> on F, Archives on G, Media on H).
>
> I am aware that 'clean install' is required to go from XP Pro to Vista Home
> Premium Upgrade.
>
> When I put in the Vista Home Premium Upgrade CD when running XP Pro, I'm
> soon told that there is not enough space on the C drive, which indeed there
> isn't. What I need to do is to format the D drive and replace XP Pro with
> Vista Home Premium Upgrade, but I'm not getting far enough to be given this
> option.
>
> So far I've fallen at the first hurdle.
>
> Help, anyone?
>
> Phil
> London SE1
> UK