Check out:
http://www.fonerbooks.com/replace.htmSee what you think of it.
As a matter of fact, maybe some others here could do the same, and let you know if it is correct material.
I think the thing to keep in mind though, is that fixing problems is easy, once you know exactly what the problem is. That's the trick.
Being able to assemble a PC is nice, and sure is good experience. Being able to change parts in an existing PC, and have them work is also good experience.
But - being able to diagnose a problem - that's the real key.
I think experience is one of the best teachers. And you can't rush that.
That is where the beauty of forums like this come in. If you can accurately describe the symptoms, you have a wide audience here. The odds are, somebody else has had it happen to them, and can point you in the right direction.