The common errors are Build 7601 and Build 7600 near the taskbar.
By giving this solution I'm not supporting piracy as I'm personally against it but just helping those who have been hoaxed into buying a fake copy of Windows either by a retailer or promotional tout. This is to help them avoid the error and message for the time being and give them time to buy a new copy offline or online, as this is the best and permanent solution to this problem.
For this keep following the steps in the order mentioned.
1.Open Command PromptGo to the start menu of Windows and type 'cmd' without the quotation marks in the search field of start menu. An option with the name cmd will appear right click on it and select 'Run as administrator' option.
2.Type the commandsWith the command prompt open via the run as administrator mode, type in SLMGR -REARM.
Press the Enter key.