XP includes a photo editor, Paint.
You can open Paint by clicking on Start, All programs, Accessories, Paint
and open you photo in Paint.
However, this is very old software and frankly not very good.
Get the following free photo editing software:
www.faststone.org
www.picasa.com
Very nice photo editing is faststone while picasa will do some basic photo
editing but is better used to organize and find your photo quickly.