I have some advise, it may not be the advice you want, but advice none the less.
I find it hard to recommend anything, because i taught myself by exploring and finding the information.
I built my first computer several years ago. I knew the basic required components, bought them and put it together. for the most part components only fit in one socket. Unless your making a high performance, gaming, server, or other fancy build, there shouldn't be much that could go wrong.
If you wanted to learn the basics of building computers, i would suggest you get an old out dated computer that isn't used any more, maybe 2 so you can take parts from one to use in another, and figure out how to fix any issues that come up. dismantle the computers and rebuild them, your books should describe the function of every part and what suitable upgrages would be good to pull from the other computer. I wouldn't not use a current computer in the event that the your or your client data is lost. look for a computer that has windows 2000 with the install disk, to avoid any installation registry issues that you make have installing XP or Vista on different computer.
1. I don't know what your feelings are about getting a job. But if you start your own business, you own a job.
2. I don't make alot of money selling part, because every other company out there is trying to get their business be selling the parts cheap as well. The same pretty much goes the same for building custom computers. Also most customers feel better about purchasing from larger more well known companies.
3. Unless your going to be purchasing a lot of products from a distributor, such as 100 Seagate 500GB Hard drive, your not going to get very much of a discount. and you still have to sell all the product before the market value goes down at other stores.
4. I was able to purchase most of the parts i need from retail stores cheaper, than buying them from a distributor. Either way, make sure you get a resellers license so your not paying the sales tax twice.
5. Most of my profit is made from service calls, fixing software and hardware issues. So unless that is the schooling your getting and the books your reading, i don't think your going to find much on the subject.
how would you eliminate a potential issue without damaging the operating system. I have heard horror stories from clients stating that previous techs would only run defrag and the tech considered that good. Other reported techs have replaced perfectly functioning hardware only to sell the client more hardware before finally finding the issue. And my worst pet peeve about bad techs is that they reformat and reinstall the OS for minor virus or operating system issues
If you think your going to be good enough to over come all the above, than i think you should go for it, as long as you don't become a horror story yourself.