Hmmm.
The method I've used for breaking passwords (which involves using another Windows machine to download special software to a memory stick) might not work with Windows 10.
Try this instead (as long as you don't mind wiping all of the documents, pictures, etc which were on the laptop):
When you get to the password screen, press the Shift key down and keep it held down.
Go to Start > Restart. (You can release the Shift key now).
That should bring up a 'Choose an Option' screen. Select 'Troubleshoot'.
From the next screen select 'Reset Your PC'.
At the next screen (telling you what will happen when you reset), click 'Next'.
At the next screen select 'Only the drive where Windows is installed'.
Click on 'Just remove my files'.
Click on 'Reset'
The laptop should reboot as if there was never any account on it.