A good place to start would be any A+ certification book.  I don't have any specific example, but they cover all the basics.  Some of it you may already know, some of it may be over your head.  But it will cover a WIDE variety of topics.  You may look at like a A+ for dummies (not calling you a dummy) as it may be easier to read and less technical. 

As with any computer manual like that, try to get a used copy or got to half price books.  New, they will be expensive.  Usually around $50-$100 depending on the book.

Good luck!