I couldnt find a definate answer about the size of th case - but looks like a mini tower. While this will be fine for a mini atx motherboard (not sure if i5's come in mini atx yet) - the PSU will not be capable of powering a modern CPU / mobo combo
I took a quick look at the interior diagrams in the owners' manual. It's got a micro-atx motherboard with 4 expansion card slots. No problem finding a new one. Micro-atx motherboards are readily available.