Is it illegal to use a hammer on a glass window pane?
Is it illegal to use a tool to open a door (to get into a car or into a house)?
Is it illegal to set a tv onto fire?

No, it is not as long as you are the owner of these objects.

But if you steal them you are a thief, just that, no excuses needed. You can live without TombRaider and your school can install Linux if they dont have the money to get a Vista license. And I am sure MS will offer very cheap licenses to schools, sometimes even for free.

In the case of editing software with notebook: Please read the license agreement and I am sure there is something written about decompiling or changing the code. I am very sure it is illegal to edit it in notepad.