I run Windows XP, and I wanted to install Windows XP 64bit on a second partition. I have attempted it a few times, and it never works. Even worse, it corrupts my original windows, and I have to perform a recovery, and then reinstall all the hotfix's. Is there a simpler/Fool Proof way to install the other OS?

There should be no problem with this.

Is the second partition already in existence? Are you sure that you are installing to the second partition when asked "Where do you want to install XP64"?

What exactly happens when you say "it never works"? Also what exactly happens to the original XP that you need to Repair it?

Also see if this helps:

Beginners Guides: Dual OS Installation of WindowsXP 32-bit/64-bit

(Takes some time to load).

I have the partition already set up. I have two hard drives. One has the first Windows, and the other one has two partitions, which I am trying to install Win 64 onto.

After the install, I try to reboot, and it says that it cannot load windows because one of the files is corrupted (ntoskrnl.exe. And it asks me to replace the file. It is a file in the windows\system32 folder, does that mean that the new install is corrupting the old one?

This has happened two times that I tried to install an additional OS

That error is indicating that the BOOT.INI has been altered as XP64 does alter it. But if XP64 installed successfully you should see a boot menu with XP64 as your first option.

http://www.computerhope.com/issues/ch000492.htm

Most of what I read and have done myself is load all Operating Systems on the same hard drive on different partitions.

I do see that you can do this on separate hard drives but I have not come across any details yet. Still looking.

Anyway if the issue occurs again you do not need to Repair the original XP. Just boot the CD into the Recovery Console and run these two commands:

FIXBOOT

FIXMBR

This will repair the BOOT.INI