The problem comes from the fact that she gave it to you and then you did the replacing of the parts, to those not so involved with computers as people like us they won't really see that and will only see the outside of the box.
I suggest you rebuild her old computer (If you have all the parts) and give her that one back then buy a case for yourself. Don't bother buying a new CD drive though, they're obsolete now.
I suggest you rebuild her old computer (If you have all the parts) and give her that one back then buy a case for yourself. Don't bother buying a new CD drive though, they're obsolete now.