Turn on your laptop and open "Power Options." To do this, click the "Start" menu in the bottom left-corner of the screen. Then select "Control Panel" and "Power Options."
Click "Adjust Brightness Displays" located at the bottom of the left pane. This opens the brightness display settings.
Increase the brightness of your laptop by sliding the brightness indicator to the right. You can change the brightness settings for two different scenarios: when the computer is plugged in and when it is relying on the battery.
Click the "Save Changes" button at the bottom of the window and your laptop's brightness settings are changed through Vista.