ANSWER:

1st you need to boot a live ubuntu disk and resize ubuntu to make room for xp using gparted
You should know xp only supports 3 primary partitions on a hdd (the partition table supports 4, guess xp can’t count)
next use the boot menu to select your disk driver for booting using the boot menu, there should be info as soon as you hit the power button at the bottom of the screen, if you cant find it read the manual for the laptop
after installing xp you will need to boot a live disk and reinstall grub:
https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows
Windows XP does not support secure boot and will not boot with it enabled

You should look into use virtualbox for running xp, assuming your cpu supports VT, you may need to enable this in your bios
You will need to use the left ctrl key when accepting the eula for windows xp in virtualbox

GM-Script-Writer-62850 from http://askubuntu.com/questions/297330