1. Get a Windows 7 installer DVD. If you don't have one, you can create a Windows 7 System Repair Disc by using another Windows 7 computer and click on Start then in the box, type in RECDISC.
2. Boot your computer from that disc. Make sure that your BIOS is set to boot from the DVD drive.
3. Select your preferred language and click on Next.
4. Instead of clicking on 'Install now', click on 'Repair your computer'. The 'Use Recovery tools' will be pre-selected under the System Recovery Options. Click on 'Next' and 'Command Prompt'.
5. Type the following 4 lines below:
c:
cd\windows\system32
ren sethc.exe sethc_orig.exe
copy cmd.exe sethc.exe
6. Close the command prompt window, remove the CD/DVD from the tray and click on 'Restart'.
7. In the log in screen, tap the Shift key five times. A black window titled SETHC.EXE should appear on your screen.
8. Type "net user" (w/o the quotes). Take note of the user account that you want the password changed.
You probably don't know it but there is a super Administrator account that you haven't seen before as it is disabled by default that's why it never appears on your log in screen. If you want to enable it, type this:
net user Administrator /active:yes
To turn if off:
net user Administrator /active:no
9. If you have another admin account that you want the password changed, for example FuzzyBear, type:
net user FuzzyBear ""
That's a double quote with nothing in between. Note that you may replace the double quotes with a new password if you want to set one right now.
You may now log in to your admin account and do whatever you like to the system.
HOWEVER, you are not finished yet. You need to undo the changes you've made to the SETHC.EXE. Reboot from the disc you used in step 2. Run a Command Prompt again and type the following lines:
c:
cd\windows\system32
copy sethc_orig.exe sethc.exe /y