well there's that but usually laptop bios's have a hardware lock once the pw is entered incorrectly 3 times. It's not a simple job of just removing battery. Usually a new bios chip or sometimes a whole new board is needed.
There's a HD password/code too, I think if you take it out and plug it into another computer it'll be encrypted.
All the above "my knowledge" which could be off, just stuff I've read over the years.