Dual booting XP with Windows 7 already installed

I have found guide for dual booting Windows 7 with XP or Vista already installed, but not the other way around.

I allocated some free space from my C drive for the XP install. I installed XP, but when I restarted my computer, I got this error, "A disk read error has occurred; press Ctrl-Alt-Del to restart dual boot".

What am I doing wrong?

Alright, I'm going to try using EasyBCD. Hopefully that will work.

But please give me your input still.

Follow method two of this tutorial. http://www.sevenforums.com/tutorials/8057-dual-boot-installation-windows-7-xp.html

I tried method 2, didn't work. I just reinstalled XP, and then reinstalled W7. Took a long ass time, but it works now.