Just download it. It's free. And you can slipstream it to a recordable CD so your original XP and SP2 are merged together, so when you format, it automatically installs SP2 for you!
SP2 download page:
Autostream download page:
And if you haven't formatted on your own before, maybe you should get your friend to help you again. Orrr, maybe it'd be a good opportunity for you to learn to do this. It isn't that complicated, provided you have basic computer knowledge. I remember having to do a clean reformat of windows 98 for the first time when I was 12...