I bought an ASUS notebook a few days ago. After careful care and preparation I had to find out that the system was protected with a BIOS password.
Removing the CMOS battery did not help because the data was stored in the non-volatile area of the BIOS.
Looking for something I found a simple solution: https://www.biosbug.com
Example for Asus:
- start the laptop and go to the password prompt
- press <ALT> + <R>
- a rescue password will show up (style: yyyy-mm-dd)
- visit the page that is mentioned above and let the side calculate a recovery password for you.
After entering this password the BIOS will be reset and all passwords will be deleted. Just save the new config. done.