Motherboard LED component-diagnostic lights and other motherboard diagnostic systems
Some motherboards now have LED lights on the board itself showing the status of the components. The main status colours are green if the component is working and red if it is not. The image below is a drawing of an MSI MS-7522 Socket LGA1366 motherboard for Intel’s Core i7 quad-core processors. It shows which components have LED(s). The motherboard’s user manual provides the colour codes.
Most motherboard manufacturers provide a diagnostic system for their motherboards, such as an error code showing at the back of the case, which can be looked up in the board’s user manual, or installed software. Here is a link to a PDF file called “ASUS PC Diagnostics Guide”, provided by the major motherboard manufacturer, Asus: