You don't need to be a super-geek to start diagnosing hardware problems. Diagnostics is an art. Specifically, it's the art of determining the source of a problem and troubleshooting a solution. No matter how good you are at diagnostics, the right tools in your hardware bag can make you better.
Here's an example of what I mean. My daughter called me at work, frustrated and upset. The DVD drive that she got for a birthday present wasn't working. After playing 20 questions about the drive, my daughter -- not yet a geek and very frustrated -- asked, "Where's the screwdriver?"
Another time her computer failed to power up. She diagnosed a bad power supply and replaced it, but when I got home, she still had the same problem. I started looking at it. I disconnected the ATX connector from the motherboard and connected it to a power supply tester. No power. I checked the AC line. When I moved the plug in the UPS power strip, bingo! There was an oxide/corrosion buildup on the plug/receptacle that was blocking power. Pull, plug, power, and the tester chirped approval. My daughter was upset -- she had to switch the power supplies back.
http://www.linuxlinks.com/portal/news/article.php?story=20060531133354535