Steps:

1. Reboot your machine.
2. Press F8 before the Windows boot screen appears.
   • Do not press F5 as used on the NT/9x series of Windows.
3. You will be be prompted with a boot options menu.
4. Select the Start Windows in Safe Mode option.
5. Click through several self-explanatory screens until your reach the familiar 'Welcome' screen.
6. Note that this welcome screen is limited to 256 colors and 640x480 resolution because the primary graphics will have been set to the Windows Safe Mode software VGA adapter. You will not be able to change this mode even in Display options, while Windows is running in Safe Mode.
7. Find the icon for the Administrator user. If the default settings of your system haven't been changed, there should be no password for this account.
   • The Safe Mode Welcome screen might display some of the other users on your system.
8. Login as the admin.
9. Press Yes at the prompt asking if you would like to continue using Safe Mode.
10. Continue on to the User Settings control panel. Here you can change any of the other passwords for user on the machine. Make any changes you want.
11. Reboot your computer. As long as you don't press any keys (i.e. F8) during the boot-up the computer will startup normally.
12. Login as the user for which you set the password.

Tips:

• You can access the Administrator account through the login prompt without logging into safe mode. If the computer utilizes the welcome screen instead of the standard NT domain login prompt, you can press Ctrl + Alt + Del twice to get to the login prompt. This is only true if you are running Windows XP Professional Edition. Windows XP Home Edition will also allow you to use this method to log on.
• Some users are smart enough to password protect their Administrator account when they install windows. If that's the case, you'll have to know that password in order for this method to work.
• There is a way to crack the windows "SAM" and system files to retrieve the original passwords Monitor, you need a program such as LC5 installed on a computer, and the SAM file in C:\WINDOWS\system32\config if LC5 is not installed on the computer that you forgot disk because as soon as you can get into the hard drive, windows is using the file so you cant copy it.
• Use SysInternals ERD Commandor to change the admin. password. Boot from the CD and select the locksmith option to change whatever password you like. Alas, this product seems to have been discontinued, however there are many other options out there for resetting the password so long as you are willing to spend a little money.
• Much simpler is simply to rename or delete the SAM file (renaming is safer). For this you need to boot the box using some other operating system on a CD and then mount the drive (otherwise Windows locks the SAM file and won't let you touch it). NTFSDOS is also a good utility for this purpose. Find the SAM file and change the first character. After you reboot, all the accounts are still there, but they all have null passwords. Note: if you rename the SAM file on XP SP2, when you reboot, XP fails to initialize and forces you to reboot in safe mode. However when you boot into safe mode you get the same message, so don't try this method on XP SP2.

Warnings:

• This method does not work with machines running XP SP2, you will need to use "safe mode with networking" instead.
• Use these instructions for ethical purposes only, please. Accessing Windows Administrator and changing passwords could be construed as illegal entry and electronic trespass in a court of law.
• This whole process is pointless if you know the administrator's password as you can easily remove passwords without going into safe mode. Assuming that your PC only has one user profile with administrative powers.