Solution:

Under Win95/98, backlight could be turned off via. APM(Advanced Power Management) and the power management of BIOS; however, this way doesn't work on WinNT because WinNT doesn't provide APM function. Although backlight is not able to turn off through APM, there is a third-parity software(Softex Power Management Controller) provides the function to turn off backlight. Softex Power Management Controller is BIOS independent, as such, the drivers can be loaded onto any APM 1.x compliant system. For detailed information, please check out the web site of Softex Inc.