What you are describing is called a BIOS password. It's purpose is to protect the laptop when it is immediately turned on. Only when the password is entered will the laptop boot into Windows when it will ask you for a user password if one has been set up.
The only way to disable the password is to going into the BIOS itself. But you need to enter the password before the laptop initializes at which point you typically press the F2 key to going into the BIOS. Laptops do not automatically setup BIOS password for itself so it must have been created by someone.
If you loaned the laptop to someone and that person created the BIOS password, then that person will need to give you the password. If that person forgot the password or you do not...