Darkened LCD

My LCD is so dark i can’t see a thing except if i use an external monitor. Its a HP Omnibook XE2 DC, it occured when i installed wrong sound drivers and kept booting to safe mode [win98se]. Should i update the BIOS? Or look for the correct LCD driver? I couldn’t get the LCD driver[Omnibook XE2 monitor] when i downloaded the drivers from the site.