Step 1. Put your hard disk of your computer in any other pc .
Step 2. Boot that computer and use your hard disk as a secondary hard disk (D'nt boot as primary hard disk ).
Step 3. Then open that drive in which the victim’s window(or your window) is installed.
Step 4. Go to location windows->system32->config
Step 5. And delete SAM.exe and SAM.log
Step 6. Now remove hard disk and put in your computer.
Step 7. And boot your computer :-)
very simple method. hope you all enjoy!!