If you have a webcam, download KeyLemon (formerly Banana Screen) and forget your passwords. It creates your face model and your face will become your password.
It's easy to use. You only have to create your face model (just press ok) and from then on, your computer will be unlocked only if you are opposite it. KeyLemon detects if you are the one opposite your computer thanks to your webcam and if it's other person it will remain locked.
It can be really useful, because thanks to it, you will not have to enter your password so many times. Furthermore you can adjust the time you have to be out of screen to lock the PC.
KeyLemon is really accurate, so only you will be able to use your computer. It's great, and in addition, it's free.