Laptop computers, or notebooks, generally have status indicator lights on the front portion of the machine. These lights provide you with the status of important aspects of the computer, such as if the computer is turned on, if it is getting power and if the battery is charged. The symbols can vary, but most vendors use a specific set of common symbols to reduce confusion.
Power On Indicator
The power on indicator is often a circle with a small line going through one portion of it. Depending on the brand and model of computer, the indicator may be the actual symbol lighting up, or may be a light next to the symbol lighting up. A solid light, in either red or green, most often means the computer is on. Many vendors make this light flash when the computer is in a low-power mode, such as when it has entered "sleep" mode.
There are two primary symbols for charge indicators. One, which looks like an electrical plug, indicates that the computer is plugged in. The other, which looks like a AA battery, indicates the status of the battery. The battery indicator may change colours depending on whether the battery is in use, fully charged or being charged.
Disk Activity Indicator
A small cylindrical shape, that looks almost like a soup can, is used frequently to indicate hard-disk activity. Any time the computer is writing data to or reading from the hard drive, this light illuminates. This is a safety precaution to make sure you do not turn off your computer in the midst of hard drive activity.