Open your laptop and check to see if there a jumper labelled clear CMOS or clr CMOS or any abbreviation that suggests CMOS. Fuse that jumper and on your laptop.
if this couldnt help, get 'Hiren's boot cd', a bootable cd that provides options for password cracking.
Else us the same boot cd to back-up the the bios on your pc. download the bios from the manufacturer's website then use it to flash the the bios rom chip. Make sure you download the correct bios for your system and flash the bios well. mostly they come on floppy disks. insert the floppy disk and restart the computer.
I hope one of these help you.