Unable to play flash games. All I get is a white box. Does anyone have a solution?

I have windows 8. I am playing Flash games on www.keygames.com. Since 16th November no games will play. It says that the Flash content is enabled. The Flash plugin is active in Firefox. I have tried a system restore to an earlier or date which made no difference.

I have tried to play games in Internet Explorer. Firefox 25, Google Chrome, Opera and Blackhawk browsers. I have sent an email to the technical support of the game I play without any help. I could not find any support for the keygames website. The computer speed is fine.

I have emptied the Flash cache memory. I do not have any error messages. I have installed the latest realplayer aswell. I can play videos on youtube. I did have a problem loading a java update which was a problem before the Flash stopped working. I have fixed this and have it installed. It says it has some security problems so it will ask permission before it can be activated. I can sign in to the game that I play but there is nothing there just a white empty box.