Yeah, basically they build them so you HAVE to take it to them to get it upgraded. The motherboard is to their specifications and the whole system is built around it. This isn't to say you couldn't add RAM or something like that, but how much of what speed would be the questions, and same goes for CPU's, god knows what that board is capable of handling without contacting the manufacturer. All brands like HP, Dell, Compaq, PeoplePC, all make their computers this way.
All in all it depends on what exactly he wants to upgrade, but generally their cases are completely different, layout is, and so is the motherboard =/