Just wanted to say a massive thank you to the OP.....!!! I'm also bumping a very old topic but the steps laid out worked flawlessly on a Windows 7 x64 machine. I'm so glad I found this thread as was literally about to give up and wipe it after spending many hours with it.
What prompted me to get here was a Microsoft forum where someone also posted some useful commands using 'cacls'. But I think because it used the group 'Everyone' and that group may not have existed on my machine it didn't work properly (when I rebooted the login screen would be flashing and no where to enter password etc.)
In regards to the guy above me, I'm only about 3 years late with my help but there is a trick to paste all the commands in via notepad to make it more manageable. Copy the command lines from this thread in a .txt file and save to a USB stick, insert said USB stick into the problem machine. On your CMD window type 'notepad'. Now open the .txt file you saved.
Copy each block of commands and paste them in - Now with a bit of luck it should automatically do all the work (you might need to hit Enter on the last one in each block).
Stupidly I created this problem myself by plugging the OS drive into a different machine (Windows 10) externally to browse the files... I guess Windows 7 didn't like me doing that, but I had the last laugh!!!
Knowledge is power, share it well !
Thanks again :)