Delete / Remove password from the desktop mainboard.
It is easy to delete the passwords from the desktop mainboard. As a general rule it is sufficent to delete them from the CMOS by taking the CMOS battery from the socket for a few minutes. PC mainboards usually have a jumper too, which can also be used to delete the CMOS. You can read in your mainboard manual whether there is a jumper available and where it is positioned.
Delete password from notebook/ netbook
The delete of passwords from laptops is more complicated than from desktop mainboards.
Here is mostly not sufficient to delete the CMOS. The BIOS chip must be completely replaced. Some manufacturers use in addition to the Bios Chip a further chip on which the password is stored.