Pleas I need an urgent help, my system Toshiba windows 8.1. Is always saying that my windows activation keys will soon expire. And the date is 8 of match 2016, pleas I need a guide line on how to activate the windows key.the last time I posted this issue I was told to connect my PC to internet that it will activate automatically,I did that but it still keep saying windows key will soon expire

Pleas I need a help here, my Toshiba satellite c55 is telling me my window will soon expire , pleas what is the solution to this problem, and the expiration date is 8 march 2016,will my system experience any damage if the expiration date relapse thank you ( my system useses windows 8.1)