Windows Vista is the initial OS to have Snipping Tool, and what it does is just capture a region (or a window, or full screen) to an image file. Of course, it lets you annotate on it before saving it to disk.
For XP, there exists many programs for that same purpose. Good examples are IrfanView (version 4.67 at the time of this writing) and ShareX, version 12.0.0.