HP Pavilion ze4400

Carefully, open the case. Be sure to save all of the screws.

Once you have it open, plug it in, and take off your shoes. Socks are OK, but don't wear any shoes. While holding it in one hand, pour as much of a gallon of water on it as you possibly can. Don't worry about water spilling on the floor, that's OK, and is, in fact desirable. Be sure to stand in the puddle, and if you feel a tingle, that's also OK. Now stay there until you are fully electrocuted. At that point, the laptop should no longer ask for any password, whether on the bios, or otherwise.

Good luck!