Use the Linux-based Offline NT Password & Registry Editor utility.
What you need before you begin:
1) A writable CD/DVD R/RW
2) A capable DVD burning drive.
3) A software program to burn the ISO image.
I cannot help you with the above 3 you are just going to make sure you have a CD to burn.
Download the bootable ISO CD image here: http://www.pogostick.net/~pnh/ntpasswd/cd100627.zip
Once you have burned the ISO image let's begin. You will need to write down or print out the below instructions since you won't have access to this forum when you reboot your machine! HAHAHA
1. Insert the CD and press any key to begin booting the Linux utility
2. You will see options like -nousb blah blah blah, just hit Enter
to accept the default settings.
3. It will search for available partitions on your computer. You should see a format similar to what I have typed below:
1 /dev/sda1 38151
2 /dev/sda2 470505 BOOT
Type the number pertaining to your R2 installation and hit enter. Good chances it will be 1. In my example above its 2. 2 <enter>
4. Hit enter
to accept the default registry location.
5. Type 1
for password recovery.
6. You will be prompted with 3 options. Select 1
to edit user data and passwords.
7. Type in the username
of the account you cannot access.
8. Type 1
to clear the password.
9. Type !
to save changes.
10. Type q
to quit out of the user data and password editing utility.
11. When you are prompted with "About to write files. Do it?" Type Y
to write changes.
12. When you are prompted for a "new run" type N.
13. Eject your CD. Take out your disc.
14. Type CTRL+ALT+DELETE to reboot the machine.
Your R2 machine should login with your desired username with no password. You can then go into Control Panel and type in your desired password again. I have tested this on R2 before with success.
The power of Linux!