I am not in the IT business but I am the go to guy for my friends. Like others, I learned by doing. Often with spectacular results.

My first "real" computer was a Radio Shack TRS 1000 build like a Commadore. It had room for two cards. So I installed a 300k modem. It came lose so I reached in and pushed the card back into the slot. My first lesson, unplug the computer, was taught by smoke and a colorful display on the TV/monitor. Okay, you learn by your mistakes. My brother, an IT pro, built my next computer. When I worked on used computers, rebuilt them and gave them to friends, I turned them off.

About a year later, I went to one of my brother's favorite parts stores and bought some goodies. All went well until the salesman asked for my name for the records. I gave it. He asked if I knew someone who turned out to be my brother. "Oh," said the salesman, "are you the brother who fried the motherboard?" I admitted it. I still hear the laughter. That was over ten years ago. Too bad, it went out of business like too many of the indie computer stores did.

I learned a very important lesson from my brother that day. There is no client/guru confidentiality in the IT world. We still talk and laugh about the day I killed the motherboard.