|Why is it that you don't know that password ? |
That's what a thief, or someone who knowingly or unknowingly has a stolen laptop, or someone who should not have the right to access the bios of a computer that is not theirs would want to know.
Laptops made in last ten years or more cannot have the bios access, system access, or hard drive access password info removed by removing any cmos battery - that info is stored on a chip other than the bios chip that cannot have it's user contents cleared by removing the power to it.
If you just want to be able to boot from a bootable CD or DVD and your laptop will not do that presently, you probably don't need to get into the bios to change the Boot Order or similar settings in the bios. See the Owner's or User's manual for the model - there is usually a key or key combo you can press while booting that allows you to change the order of the devices you boot from, that will work that one time, but not change the setting in the bios settings. Also, you MAY see a line on the screen while booting "Press xxx to change boot device" or similar.