Max

You over-wrote some necessary boot files that Vista installed and used on
your XP partition (in a dual-boot scenario). So Vista no longer exists in
the boot sequence. You will have to re-install Vista so that it can re-write
this information.
You could first TRY booting from the Vista media, and doing a "repair
start-up", but I really don't know if this will help in your
situation--maybe somebody else knows.
PS. when setting up a dual boot, it is almost always imperative to install
the newest OS last.

--
Maxwell Bluemeanie
"marc.nutty" <marcnutty@discussions.microsoft.com> wrote in message
news:C2A237B9-86D4-4B82-A3E1-7DE9C581BF25@microsoft.com...
> Hi,
>
> A week ago I had XP and Vista on seperate HDDs (using a dual-boot setup).
> This weekend I decided to format XP HDD and install clean XP again.
> (needed
> doing). However, now when I boot up my machine, it automatically loads XP
> with no options. Vista still exists on the seperate HDD. I've also
> arranged
> boot-up preferences > CD/DVD then > HDD etc... (in same order as before).