The dimensions for the motherboard are, 30.5cm(L) x 24.5cm(W) see if there is enough room in the case for it, and if you do, then it is fine to use it, but you may have to have the drill handy.
I don't really want to add more to your problem, but you may of overlooked the PSU, and it may not be compatible with the motherboard. (Dell switches the pins around so you have to use Dell PSu's,) again I don't know if Sony does the same.
I know its not ideal, but as you are 15, you could ask your Dad for some money for a case and PSU. $30 will get you something that will last you until you get more money for the a decent case and PSU.