|Watch the screen when you first turn it on, it should tell you what key to press to get into the BIOS. Then look under the security settings. It should have the option to set a boot password.|
Not to sound rude but something doesn't sound right here. You say you want to change the password indicating you have already set one, and if so shouldn't you already know how to do it? If this laptop is stolen and you're asking how to get past the BIOS password, you won't get help here.