Boot from the Windows XP CD and press R during the setup to start the recovery console. Select your Windows XP installation from the list and enter the administrator password. At the input prompt, enter the command FIXMBR and confirm with y when asked to do so. Then reboot the computer with exit.
I'll test this and make a new video as soon as I complete some projects already in progress and can free up my test computer.
I personally see no harm in leaving grub there, with Windows as the only option, but what the hey. Won't be a big deal to do once I get time.