More dangerous is the loss of previously written files, or even an entire hard disk, which can occur should a power problem strike while your computer is saving a file. Network fileservers constantly writing to disk are particularly susceptible. Unfortunately the situation won't be getting better anytime soon. It takes approximately a decade to get a new power plant on-line, and concerns about nuclear power and fossil fuels have stifled the construction of new generating facilities. We'll use a nearby lightning strike as an example, although it is just one of countless problems that can strike your system.
Lightning strikes a nearby transformer.
If the surge is powerful enough, it travels instantaneously through wiring, network, serial and phone lines and more, with the electrical equivalent force of a tidal wave. The surge travels into your computer via the outlet or phone lines. The first casualty is usually a modem or motherboard. Chips go next, and data is lost. The utility responds to overvoltages by disconnecting the grid.