ok , here's a more understanding guide.

1. Start your computer with Windows 7.

2. Download EasyBCD. -->

3. Run EasyBCD and go to Manage Bootloader options. Choose the "Delete Vista Bootloader (to restore xp boot.ini)" option.

4. Now start your computer as you would start normally. It should enter XP.

5. Under XP, delete your Windows 7 partition, or do anything you want with it.

That's it