Briteness on laptop

Usually you have an "Fn" or Function key on the lower left-hand side of your keyboard between the 'Ctrl' key and the 'Alt' keys. Hold this 'Fn' button down, while pressing the Function key along the top row of keys on your keyboard that has a little picture of a shining sun on it (usually the 'F7' key). Sometimes the little picture of the sun is a lightbulb instead.

Cheers!