Just before your post, there was one by Jdarling about overlaping rectangles.
The code they eventually came up with seems very simple and effective. Since Im in a similar situation to yours (limited high school education lol), I thought Id give my opinion: why don't u simply check for rectangle overlaps on two axis? i.e. check if the vertical face (front) of one box overlaps the other, and if it does, do the same with another face (top). if you get two 'True's the boxes intersect.