Step.1 Go to Start menu and search for cmd, you will get cmd.exe in search result here do a Right Click on cmd.exe and click on Run as Administrator, and you will get Command Prompt.
Step 2. Once the command prompt is opened now type the following command,
SLMGR -REARM , make sure you type the same command without any mistake,
and also ensure that command
Step 3. Once you typed the above command in command prompt window then hit Enter button on your keyboard to execute the above command. Step 4. After you hit enter a confirmation window
Step 5. Now Restart your computer you will not get that error again like Windows 7 build 7600/7601 This copy of windows is not genuine.
Credit : http://www.itechfever.com/how-to-fix-windows-7-not-genuine-error/
