PC Power Failure and PC Advisor
When you connect any computer to a wall socket you are drawing power from a blind source. You have no idea how clean, stable and secure the electricity is coming through that socket unless have already fitted a power protection device.
I found this piece on the website for PC Advisor - a forum on PC Power Supply Failures. The every day wear and tear on computer power supplies caused by power problems such as spikes, electrical noise, sags and surges will eventually lead to power supply failure. This can be prevented with a good UPS or slowed down by installing some form of filtering.