I when I was in grade 5, I loved using my brand new computer my dad got me. I was on it all day. When I turned 14, I wanted to become a computer technician.
I got my chance to work in computers when I got older. I wanted to see if it was right for me. I volunteered in a computer store locally here helping them do web design and graphics design while they taught me how to repair computers.
I realized after 3 months volunteering there, it was something I could do. I had no problems diagnosing PCs and figuring out what was wrong with them.
PCs could have anything wrong with them. Googling is your friend!
What differs standalone computer stores from big box computer stores is that you can get better more expert advice and source hard to find components.
Smaller repair shops can have over 100 suppliers that they source from. I found the prices that smaller companies are alright.
The problem with the computer repair shop business is that not many people use PCs no more. More and more Tablets and Smartphones are replacing general computer usage scenarios. Might be better to sell and repair cell phones in general I think now.
Laptops outsell desktops nowadays and laptops are disposable now rather than to be fixed.
I quickly understood that you can still make a descent living fixing PCs ($18/hr approx) but you need a side job too if you stay doing this work.
I do graphics design on the side to supplement my income.