On a laptop,if this is a BIOS password you will need to contact the laptop mfg customer support support.
If this is a desktop computer then you can use the Clr - CMOS jumper.
If it is a password for logging into Windows, then please search the net for "Windows Password Recovery". Lots of people have already written up various step by step instructions complete with pictures/screen captures to walk you through this better than I could.