Laptop connect to tv with hdmi cable

I am trying to hook up my HP laptop to my Sony Bravia Tv. I have an HDMI output for the laptop and an HDMI cable. I have tried simply plugging the cable into the TV and the laptop but when I do that the tv does not show the picture from the laptop a black screen comes up that says "Unsupported signal. Please check device output." Can I hook this up with just an HDMI cable or am I doing something wrong? i already tried with the fn key . but my laptop did restore before . or my laptop already without the software ? or where can i get the software in my laptop with internet