I got this from the planet 64 amd newsgroup.
I had winxp 64 installed.I then installed Vista RC2 build 5744. I had a copy
of Xp home kicking around and thought I would load it ,so when vista comes
out I will use it to upgrade to vista. This way I can keep my win xp 64 &
dual boot. After installing XPhome I could not dual boot error message was
(ntoskrnl.exe is corrupted or missing) I tried everything I could think of
to fix the dual boot. I fail miserbly. I came accross this msg. in the
newsgroups on Plantnet64 amd. I thought I would give this a try. I followed
the instructions carefully. It worked I now can boot vista using (Vista Pro
Boot Manager). I can boot to vista Or Xp64 Or xp home 32. If u have had a
hard time setting up dual boot after installing xp home try this it worked
for me.
To restore your dual boot of XP64 and XP32 you will need to run the recovery
console from the XP32 install CD.
When it asks you which installation you want to log on to make sure you log
onto
the XP64 installation.
From there you should run the command "bootcfg /list"
This will find and list all currently installed versions of windows on your
system. After you run that you will need to run "bootcfg /rebuild"
It will then search for the needed boot information you will get a prompt
such as
this:
Total identified Windows Installs: 2
[1] C:Windows
[2] D:Windows
Add installation to boot list? (Yes/No/All)
You should type "all" and hit enter
From there you will be asked to Enter the Load Identifier.
This is the name of the operating system. When you receive this message,
type the
name of your operating system, and then press enter.
This is either Microsoft Windows XP Professional or Microsoft Windows XP
Home
Edition.
Then you will be asked to enter OS load options:
When you receive this message, type "/fastdetect /NoExecute=OptIn" (for
XP32)or
"/fastdetect /NoExecute" (for XP64) then press enter.
You will be asked the same questions for each OS you have installed.
after you have done this you will type "exit". the system will reboot.
You may notice that there are 3 choices after using this to repair the dual
boot.
if this happens goto the boot.ini file in the root of C: and open it with
wordpad
or notepad. remove the extra line and save the file.
Make sure that when you do this that the box for "always use this program to
open
this kind of file" is unchecked.
You should be able to boot into both OSs properly now.
Thanks to BTJ for posting on Planet64 AMD