My go-to tool for resetting forgotten windows passwords used to beĀ Offline NT password recovery
It still works fine, but I discovered that the underlying tool that does the resets is available on other distributions including Ubuntu Live CD (after apt-get) and it’s fully baked into my favoriteĀ System Rescue CD
That tool is chntpw
Even though the manual page says it’s for Windows NT/2000, so far it works on more modern windows too (local users):
Windows XP
Windows Vista
Windows 7
Windows 8
Windows 8.1
Windows 10