Activate Windows 7 Again and Make 100 % genuine:

If your screen goes black and flash error (this copy windows is not genuine) then here is the solution.Simply download file from the given link and follow these steps.

Link :-

http://www.mediafire.com/?kuieehxcw4n8d44

Steps :- 
1. run cmd as admin and paste this code and press enter
dism /online /remove-package /PackageName:Microsoft-Windows-Security-WindowsActivationTechnologies-Package~31bf3856ad364e35~x86~~7.1.7600.16395

for 64x: dism /online /remove-package /PackageName:Microsoft-Windows-Security-WindowsActivationTechnologies-Package~31bf3856ad364e35~amd64~~7.1.7600.16395

2.run 7loader4 as admin, press select task, on press select choose an OEM,
then press install info 32 if 32x install 64 info if 64x

3.run removewat as admin. press remove WAT and wait for program to 
close itself.

4. reboot and enjoy!