Found this trick on http://4sysops.com/archives/forgot-the-administrator-password-the-sticky-keys-trick/
- Boot from Windows PE or Windows RE and access the command prompt.
- Find the drive letter of the partition where Windows is installed. In Vista and Windows XP, it is usually C:, in Windows 7, it is D: in most cases because the first partition contains Startup Repair. To find the drive letter, type C: (or D:, respectively) and search for the Windows folder. Note that Windows PE (RE) usually resides on X:.
- Type the following command (replace “c:” with the correct drive letter if Windows is not located on C:):
copy c:\windows\system32\sethc.exe c:\
This creates a copy of sethc.exe to restore later. - Type this command to replace sethc.exe with cmd.exe:
copy /y c:\windows\system32\cmd.exe c:\windows\system32\sethc.exe
Reboot your computer and start the Windows installation where you forgot the administrator password. - After you see the logon screen, press the SHIFT key five times.
- You should see a command prompt where you can enter the following command to reset the Windows password (see screenshot above):
net user your_user_name new_password
If you don’t know your user name, just type net user to list the available user names. - You can now log on with the new password.
