Basically, I took apart my macbook a1342 without any idea what I was doing. Lets face it, the internet is little to no help when it comes to the reassembly stage. As of now, the macbook turns on, (the fan starts spinning and it makes a start up noise) but the screen remains black. Because of my inexperience, I doubt I'll be able to correct the problem.

So my question is, since the computer does turn on, can I hook it up to an external monitor and an external keyboard? I'm thinking the macbook could be put under a desk and used just like a PC computer tower. Will this work if I run out and buy an LCD monitor?

It depends what the issue is. If the logic board is bad, then no. Your issue could be as simple as an unplugged temperature sensor causing the machine to halt startup thinking it is overheating.

we do offer a repair service for $95 labor plus part cost (if parts necessary). We'd put it back together for you if that's all it needs.

How are these types of cables supposed to be reattached?

you just push them in from the top. they snap in place.