You will lose the Vista boot option. You can then fix that. See my blog for
details of how I did it.

http://msmvps.com/blogs/xperts64/arc...Vista-x64.aspx
--
Charlie.
http://msmvps.com/xperts64


"Lee Steele" <rleesteele@comcast.net> wrote in message
news:15171788-236A-4CD3-8C12-56A44A90A229@microsoft.com...
>I have a Dell Inspriron E1705 Desktop running Intel Duo 2 Core T2500 at
>@2.00 GHz with 2 Gig of memory. The hard drive is 91.75 GB. When it
>came from Dell, it had a 47 MB EISA Configured partition for Dells'
>diagnostic tools, a 4.93 GB Primary partition with Dells disk restoration
>program and the remaining 86.5 GB was in a primary partition. I spilt the
>primary partition into a 39. GB Primary partition for Windows XP PRO Media
>Center 2005 and a 47.5 GB logical partition onto which I installed Windows
>Vista Ultimate RC2.
>
> I am quite happy with the way Vista Ultimate performs on the laptop. I
> did not think to download the 64 bit version when it was available, so
> I've downloaded the trial version of Windows XP Pro 64 Bit and would like
> to install it on the partition that currently holds XP Pro Media Center,
> replacing Media Center with XP Pro 64 bit. I want to see how a 64 bit OS
> works on the laptop before Vista becomes available to the public.
>
> If I format the 39 GB primary partition which holds Media Center to
> install XP 64 Bit, will I loose the capability to boot into Vista on the
> logical partition? From what I've read on these news groups, I can not
> "upgrade" to XP 64 Bit, but must do a clean install.
>
> If I do loose the ability to boot to Vista after the format of the primary
> partition, can I do a repair using the RC2 DVD to restore the boot files?
>
> Thanks in advance for any help.
>
> Lee Steele