As discussed on page Cracking OS Password, there are a lot of tools available to accomplish this purpose. But cracking into someone's PC is unethical.
This technique can serve as a remedy for forgotten OS administrator password.
This technique can serve as a remedy for forgotten OS administrator password.
Below is demonstrated Konboot. This tool is available in both free and commercial version. You can download it here.
Here we go
Step 1. Extract the downloaded file any where you like on your system.
Step 2. Now only insert a target USB drive for Konboot to any USB slot and detach all other USB drives if pluged-in.
Step 3. In extracted files, find a file with name KonBootInstall.
Step 3. Open this file in Run as administrator mode.
Step 5. Select the drive and chose Install to USB stick (with EFI support). You can chose other options too to install Konboot on respective devices.
Step 6. Wait for 5 seconds while the process finishes and your USB stick is ready.
Step 7, Boot from this USB stick.
Step 8. After booting with this device, normal login screen will be displayed as usual with a password box. Just hit enter. And it's done.