Are you talking about clickPLAY3? I tried to search for a game called 'justclick3' and got no results. If it is clickPLAY3 then all you have to do is click around the screen and objects will begin to move then you press the play button when you find it.
As I'm fairly certain you mean ClickPLAY3, as justclick3 doesn't exist, it is a point and click game. Interact with the different game levels to find the play button. When your mouse arrow turns into the glove, it means that you can interact with the object the mouse is over(in case you were too silly to know that).If you want a good score, try to do so in as few clicks as possible. good luck.
Update your browser to something faster like Firefox or Google Chrome. Have the browser updated to the latest version. Update your adobe flash, have JavaScript on then refresh the page. It should work after you complete all of those things.