Why do computer Hardware Fail?

Overheating is the major reason for computer hardware failure. In some major cases, it could result in smoke or even fire.

Power supply manufacturing mostly use cheap components that could result in easy component burning due to overheating. That's one of the reasons that power supplies could be the first to die in the computer.

Hard disks are at high risk of failure due to the physical movement that happens in hard disks. This could result in having a bad sector on the hard disk. If a hard disk doesn't fail in the first few months, it will probably live long.

Fans are ranked among the components that could have problems fast. This is due to the wear effect resulting from the fast moving parts inside the fan. Also if it's a CPU fan, it could be ruined from the high temperature CPU produces.

Water can conduct electricity through the hardware circuit boards which could result in a short circuit inside the boards which can either cause great damage to the components or a very high temperature in a specific point on the board that could burn components.

Whenever a computer is forced to shut down, there's a probability that the computer could generate corrupted files. These files could damage the computer hardware on the long term.

If a computer falls on a rough surface that exerts some force on the computer, it could damage circuit components or even break the board itself.

If an electricity black out happens while you're using your computer when it's plugged, there's a possibility that a high current could appear in the power lines powering the computer. This could burn components immediately. (See Why PC users hate Mac computers?)

Some capacitors that are placed on motherboards or power supplies could result in the complete crash of the whole computer. This normally starts to happen as time passes as the charges inside the capacitor are critical in determining the capacitor's lifetime.

If the computer user uses over-clocking on any of the computer components, it could cause hardware failure, as over-clocking results in heating and heating is the opposite of hardware lifetime. (See What are the benefits of studying computer science?)

Sometimes the manufacturing factory does a mistake in the quality control unit that could result in the failure of some of their products.