Ok whether you are downgrading from 2.71 or playing tetris on 2.80, the Tiff exploit seems to be very unstable and does not always run. Well I think the solution is that you have to do this.
When you go into the PHOTO section immediantly select the folder with the exploit (Pong, Tetris etc.). And it should work. Remember immediantly. The quicker you get into the PHOTO section and the relevant folder with the exploit, then the better chance it will start up and not just crash your system.