This can also happen with brand new components, as anyone who works in a computer store knows.

"My friend's system had died due to a blown PSU, so I told him to put his RAM in another system for testing. Moving the RAM to a second system resulted in... you guessed it, a second dead PC. I figured he had just been careless and duly chastised him. Deciding this type of work was best left to the pros, I took the RAM home with me to test on my system. And you guessed right, a third dead PC..."

Also, as computer technology progresses, incompatibilities with older parts are introduced, meaning in some cases parts that fit perfectly well in your system may go up in smoke as soon as you turn the power on.

How Not to Kill Your Computer This Way

Be diligent. It's hard to protect your system against defective new components, but if you are adding something old or second hand, make darn sure that you know it works and is compatible with your computer's technology before plugging it in (or at least make sure you have a fire extinguisher handy).

If one of your systems suffered a power supply failure or other major damage and you need to test which parts survived, don't do the testing with a brand new system. If you or your friends don't have an expendable system to test with, take the wreck into a computer store and have them test it. It should be worth the price to avoid the risk of having a damaged RAM chip or video card toast your next system too.

Power On, Brain Off

It's a little disappointing to see this particular category so high up on the list, but then all of us have had our share of brain-dead computer incidents, things that you just know you shouldn't do, things like plugging and unplugging cables inside your case with the computer on.

"I was frustrated one day because every configuration I had set up would not read my second slaved hard drive. All the jumpers were set right, cable was perfectly fine, and still no second hard disk. So with the computer on, I finally noticed with my last try that the power cable was not in the second drive. I then decided to plug the power connector into the second hard drive with the computer still on. I'm sure you can figure out the end result."

Just for the record, nothing inside your system should be touched while the power is on. I don't care if Joe at your local AlphaBetaGamma computer store told you that floppy drives were hot swappable, just don't do it!

"Once, in my early days of Hardware work, I decided to swap in a hard drive while the computer was running (It was taking a long time to shut down). Unfortunately, the Molex connector on the Hard Drive was upside down, and when I attempted to connect it, I put the connector in off centre, creating sparks. I then dropped the Hard drive (steel side down) onto my new graphics card. Sparks went everywhere, and I lost a hard drive and a video card..."

Another common source of amusingly pyrotechnic computer disasters is that little self-destruct switch that most power supplies possess; that's right, the red switch that changes between 115 and 230 volts. Changing this to the wrong setting can cause a power supply failure as in the first part of this article in a matter of seconds. You really should know better.

"My friend was having booting problems. Figuring it had something to do with his hardware, he turned the system around. Seeing a switch, he figured it might fix his problem, so he decides to flick it... 120v to 240volts... a huge white light illuminated inside his case and then his computer gurgled to a halt."

How Not to Kill Your Computer This Way

Don't be an idiot. You have a power button; use it.