Windows 7: Fitting a Micro-ITX motherboard in an ATX case?

This is less of a "case mod" question, and more just a basic question about cases.

I was given an case for an HP computer a while back. It seems only one or two years old. It has most of the original case parts within it, along with some wires. Now, a friend of mine has an smaller computer in a Mini-ITX case, and has been looking to upgrade both his power supply and his graphics card. However, most graphics cards don't seem small enough to fit within his case (height wise, at least. He has enough room in both length and width), and there's only a select number of Mini-ITX power supplies on Newegg (and the highest wattage is 400w). Logically, I figured he'd be able to take my extra case and fit everything else in there, but I was unsure if it would fit properly. Would the motherboard in the back line up correctly in an ATX case? Would there be screws in the correct places?

If this is on a case by case basis (pun intended), he owns an Acer Aspire X3200, and I can provide pictures of the board if needed.

The answer is possibly. What I would do is pull the back off and look at the holes for the stand off's. Take a piece of paper and trace the Mini-ITX mobo's mounting holes and then with a hole punch...punch them out and then hold the paper with the IO pointed towards the case IO panel and see if it lines up with some of the holes in the back. The IO shield out of the Mini case likely this won't fit the new case so the IO's won't have a shield which isn't the end of the world but not ideal.