Default screensaver kicks in on my desktop, no problem. But not on my laptop. Preview works on the laptop of any screensaver I choose. I only have the default ones on there (Bubbles, 3D text, etc). I thought it might have been to do with having my laptop connected wth HDMI to my TV, but on disconnecting the HDMI and waiting, it still didn't kick in. There's nothing else to do except select a screensaver, press Apply and OK. Any suggestions? Laptop is i5, W7 Pro.