When you forget the password to your laptop, you can factory reset your laptop or using software to reset the forgotten password.
You should realize the following issue before you take action to factory your laptop.
1. Factory reset a laptop will make all data lost on your laptop.
2. Factory Reset all reset the partition to its original state which means that the partition your created will be removed.
3. No meter what version of operating system you are using, the current operating system will be reset to the original system which you upgraded from.
So it is not recommend you factory reset a computer if you have any other solution to solve the problem. You can find the possible factory reset way for your laptop here.
4. How to factory reset lenovo laptop
If you forget the password to laptop, I recommend you use password recovery software to recover the lost password instead of restoring it to factory settings. There are many free or premium programs can reset or recover the forgotten password for Windows 8, windows 7, or windows vista easily, such as Windows Password Geeker, Chntpw. You just need to download it to another computer and create a bootable disk and use it to boot the locked laptop, then you can reset password for any user account. More step by step guides to use these program will be found in I forgot the password to my laptop how to get in.