How do I adjust the brightness on my laptop? Its a Compaq Presario V2140US

1. Press down the Fn key at the lower left end of your Compaq Presario keyboard. Keep the button held down and tap the F7 key to decrease the screen brightness by one step.

2. Tap the F7 key again with the Fn key still depressed to further decrease the brightness by one step. Continue hitting the F7 key until you reach the minimum LCD screen brightness.

3. Hold down the Fn key and tap the F8 key to increase the Presario's LCD screen brightness by one step. Keep pressing the F8 key until you reach the maximum brightness for your screen

Usually on most laptop you will to select the "fn" key while holding that down its typically the up and down arrow. So hold down Fn key and tap up or down arrow to change brightness levels.

Also sometimes the symbols (fn symbols) are cog wheels (resembling the sun)