FSX DX10 Install and Vista Upgrade

Ok
I'm about to purchase FSX Acceleration and to take advantage of DX10 I will also need to upgrade from XP to Vista.
What's the best way of doing this?
Do I simply install the Vista upgrade over the top of XP?
Do I delete the whole hard drive (after making backups), install Vista on a blank drive and reinstall FSX, etc.?
Do I partition the drive into two (plenty of room), then install Vista on the second and make it dual-bootable (no idea how to do any of this though!)?
Or something else?
My PC is only used for FSX.
What do people recommend?
Thanks.
Sean
I'm about to purchase FSX Acceleration and to take advantage of DX10 I will also need to upgrade from XP to Vista.
What's the best way of doing this?
Do I simply install the Vista upgrade over the top of XP?
Do I delete the whole hard drive (after making backups), install Vista on a blank drive and reinstall FSX, etc.?
Do I partition the drive into two (plenty of room), then install Vista on the second and make it dual-bootable (no idea how to do any of this though!)?
Or something else?
My PC is only used for FSX.
What do people recommend?
Thanks.
Sean