Photoshop CS2 tools won't work, how do I fix them?

When you say they don't work, do they show up (as your mouse cursor) at all when you click them? Some tools, especially dodge and burn won't work on certain files or shapes. But sometimes photoshop can be dysfunctional. I would try to use them over something like a jpg photo and see if they work on that, if they don't you may need to get a new version of Photoshop. I recommend CS3, way better than CS2.