Windows Activiation Issue

I get a popup message saying "This copy of Windows must be activated with Microsoft before you can log on. Do you want to activate windows now?" with options "yes" and "no". I already clicked yes and activated it, but when I log on i still get this message. If i click yes again it says that I have already activated this copy of windows and restarts. If I choose no, it restarts and brings me back to the same message. How can I get past this? Even though it's activated I still get this message and it prevents me from logging into windows.