The easiest way would be to open it up & remove the battery powering the cmos/bios thus forcing it back to defaults on restart i.e. no password. Alternatively, you can look here:
How do I reset a BIOS password?
I'm not sure whether something like that would have a jumper setting on the motherboard to reset the cmos as you often see on desktops mobos. Worth a look around google I would think.