I know that a lot of users reinstall Windows if they have forgotten their password because they cannot figure out how to get into the system again. I’m using the Trinity Rescue Kit to reset the Windows password. You actually have the choice between setting it to a blank password or changing it to a new one.

It can be run from a bootable CD, USB device or network over PXE. The bootable CD is my choice and I always keep one around in case of emergency. Just boot from the CD if you cannot login into Windows anymore because it asks for a password that you cannot remember.

You can start once the message “Welcome to Trinity..” appears on the screen. Use the command winpass -l to list all usernames of the system. Now enter winpass -u (for instance winpass -u Martin). This will lead to a series of dialogs, make sure to press n when asked if you want to deactivate Syskey.

You are given a choice to (1) remove the password, (2) set a new password or (3) make the selected user an administrator of the system.

That’s actually just one tool that the Trinity Rescue Disk offers. I could write about other useful ones if you like. Oh, one last remark. The file system is based on Linux which means that you will not see the usual c,d,e drives like you do in Windows. Hda, hdb, hdc are the hard drives connected to your computer and the numbers behind are the partitions of those hard drives. Hda1 for instance means the first partition of the first hard drive which is usually the location of the Windows installation while hdc2 would refer to the second partition of the third hard drive.

The author of Offline NT Password & Registry Editor provides a bootdisk for his program while austrumi already is bootable. A detailed instruction for the first tool can be found at the authors website, with Astrumi you simply enter nt_boot when the command prompt appears.

You could also try to bruteforce your way in again but this is not recommended because the other two methods are easier and faster.

Last but not least this was taken from a user comment and not checked.

1) copy cmd.exe out of system32
2) rename as logon.scr
3) paste it back in system32 and replace current one
4) log off and wait for the screensaver. it will be a command prompt. use [net user]