Windows 7 Metro UI Original/Revamped Login Screen Installation Guide:

Note:
1. Install it at your own risk. I am not responsible for any damage caused by crashing of the PC. 
2. This should work with Windows 7 SP1 for both 32bit and 64bit systems.
3. This Login Screen is only compatible with English version of Windows 7. Other language MAY crash the system.
4. Make sure that your user account has administrative privilege so that you may be able to replace the system files.
5. Check if your operating system is 32bit or 64bit. For that matter, refer http://goo.gl/KNlqri

Install:
1.	Save all your work in case your computer crashes.
2.	Install "InstallTakeOwnership.reg".
3.	Open Explorer and in addressbar type %windir%\system32 and press ENTER.
5.	Look for "authui.dll", right click on it and choose Take Ownership.
7.	Make a backup of the file by renaming it to "authui.dll.bak".
8.  	Choose your preferred authui.dll file and copy it to your system32 folder.
9. 	Test the login screen by pressing Ctrl + Alt + Del / Alt + Win or by simply logging off.
10.	In case you are greeted with a black screen, follow the recovery steps below.

Recovery:
1.	Do a cold reboot. Press the restart button or press power button for more than 5 sec or even if that doesn't work, yank the power cord :p
2.	Now before the generic boot screen comes, press and hold F8 button until a menu appears.
3.	Now select "Repair Your Computer" and wait for windows to load your files.
4.	Click Next and then select your computer account.
5.	Finally Select the Command Prompt option and type this: 

	+---------------------------------------+
	|	cd %windir%\system32		|
	|	del authui.dll			|
	|	ren authui.dll.bak authui.dll	|
	+---------------------------------------+

6.	In case you forgot to make the backup or the above commands do not work, type sfc -scannow although it is a much slower process.
7.	Restart the computer. This should fix the problem.
