Why would someone want to block my computer?

I have just received this message on my computer screen, which says that “Your Windows (Microsoft) Computer has been blocked”, and that I have to get in touch with technical support for help. Is it just me or this message looks really fake? i don’t believe that there is something wrong with my computer.
If there is no need to call this technical support, how can I remove Your Windows (Microsoft) Computer has been blocked pop-ups?