Crash~Override 0 Junior Poster

Hey guys I've found this guide pretty good. It's straight from my site www.k2labs.com.

If you've been using Windows XP for a while now and want to try out window 7 or vista, you might have tried dual booting!
In that case once you installed windows 7 or vista, you may have noticed that your windows XP entry has disappeared. But do not worry. Your windows XP is still there. The only problem is windows 7 just overwrote the windows xp bootloader. This is a easy fix. Just follow the steps below.

Open an elevated command prompt (Start > type "cmd" > right click on "cmd" > run as administrator)

To create an entry for Windows XP type the following. You can replace "windows XP" with any name that you want it to show.

bcdedit /create {ntldr} /d "Windows XP"

Now specify the partition where windows XP is installed. Here I have used my E partition. Choose the partition (B, C, D, E, F) where you installed your XP.

bcdedit /set {ntldr} device partition=E:

Now to set the path type...

bcdedit /set {ntldr} path \ntldr

Type the following to add this boot loader to the boot up screen.

bcdedit /displayorder {ntldr} /addlast

Restart and you are done!

If for some reason you get an error and are unable to boot into windows XP, then get back into your windows 7 installation and download the attached files and paste it in your WIndows XP partition's root directory.

Source: http://www.k2labs.com/