Access the bios to change the boot

Hello everyone,
Who could help ? I have a Dell Inspiron laptop and I have the password to access the bios, to change the boot and reinstall Windows. I'd like to flash this one and remove all of this words password.
When I tried to remove, I do not see the battery. I tried to remove the battery ignition and hit five seconds, but nothing about it would be too simple.
Who can help me?
Thanks.
