Well, I don't have an engineering degree. As a matter of fact I don't have ANY kind of computer degree but I can build them with my eyes closed. There are plenty of tutorials out there on how to put a computer together from scratch.
All it takes is the desire to build one and some basic assembly skills. Take one apart and look inside. Basically, these are the parts needed to build a computer. If you feel that you can replicate that with newer hardware then maybe you can build a computer.
If you're intimidated by what's inside then maybe you shouldn't attempt it.
Assembling the machine (hardware) is only 1/2 the job of building a good stable machine. Knowing your way around Windows and other apps (software), tricks and (registry)hacks, can turn a so-so machine, into a solid rig.
Of course, we all started somewhere, and things are easier now.
* Overclocking with DIP-switches, wire wrapping pins,pencil mods,etc... was a PITA.. though rewarding.