There are many different types of power problems. At most, users might experience their keyboard locking up, a mysterious system re-boot, or screen flicker.
Short term decreases in voltage levels.
They are the most common power problem. These are typically caused by the start-up power demands of electrical devices such as compressors, motors, elevators, etc. Electric companies cope with extreme power demands by systematically lowering voltage levels in certain areas for hours or days at a time. The end result can be data loss or corruption. Sags also reduce the efficiency and life span of electrical equipment.