Hi all, Thanks for the help in advance. I'll try to be as concise as possible. My Mac mini (Core Duo, 1gb, 320 gig if I remember correctly - it's from '08 I think) has started to randomly (well...) restart - by which I mean it suddenly switches off and on again in an instant, as if you hold the button down until it's off and press it again immediately to turn it on - but much quicker. It's instant to the chime. So far I've observed this behaviour as linked to maximising video, both flash on the web (though never with YouTube if I remember correctly) and iTunes on the harddrive. So what happens is you're watching a video, maximise it and instantly or after a few seconds you hear a click and the chime and see the startup screen. It doesn't always happen by any means, but it is happening increasingly. Advice massively appreciated.