To activate Windows in an emergency:-
1. Click on start menu.
2.Type cmd in search field.
3.Right click on cmd file and click onÂ Run as Administrator.It is must to run command prompt with administrator privileges.
4. Type SLMGR -REARM (SLMGR is Windows software licensing management tool. REARM command will reset the licensing status of machine) and press enter.
5. Now you will see a confirmation window, click on OK.
6. Restart your PC.