When a Windows Vista-based computer resumes from a low-power sleep state, the display brightness may change.
This problem occurs if one of the following conditions is true:
You temporarily change the display brightness before you put the computer to sleep by using Windows Mobility Center or by using function hotkeys on a mobile computer. Windows Vista stores a brightness preference in power policy and reapplies that preference every time that the system resumes from a low-power sleep state, such as sleep or hybrid sleep.
The computer BIOS change the display brightness when the system resumes from sleep.
To permanently change the brightness of the display, follow these steps:
Click Start, click Control Panel, and then click Power Options.
Click Adjust Display Brightness.
Change the display brightness of the computer, and then click Save changes.
Note If the computer does not display the Adjust Display Brightness option, check with the computer manufacturer for an updated BIOS to support this option.
Windows Vista Ultimate, Windows Vista Enterprise, Windows Vista Business, Windows Vista Home Premium, Windows Vista Home Basic, Windows Vista Ultimate 64-bit Edition, Windows Vista Enterprise 64-bit Edition, Windows Vista Business 64-bit Edition, Windows Vista Home Premium 64-bit Edition, Windows Vista Home Basic 64-bit Edition, Windows Vista Starter