I'm afraid you can't log-in to your OS without the password. You may want to disconnect the keyboard from your laptop, while it's powered down and use a wired/wireless USB driven keyboard to see if you can input password at lock screen and gain access to your GUI. If you've lost your password and don't know how to gain access, you're out of luck since we don't advocate bypassing security measures.
Last note, you should pass on the make and model of the laptop as well as it's SKU.