My camera wont turn on at all

my camera suddenly stopped working and is now just a black screen 24/7 although the lens is up. I have tried following other guides although I don't think it is the actual on and off button that's the problem as its not stuck or anything and still clicks. I have also tried using different batteries incase that was the problem but still no luck. Any help would REALLY be appreciated as I really do not want to have to buy another. Thanks