@insaneYLN
If you are installing Windows 7 after XP, then it will be very simple. Windows 7's boot-loader will automatically add XP to itself.
The above mentioned process is required only if you install an older version after first installing a new version. Like, installing XP after Vista or 7.
So, just go ahead, pop-in the Windows 7 DVD, and follow the instructions. Windows 7 is the easiest-to-install OS to date.