Earlier today when i touched the aluminium part of the keyboard on my iMac, it felt tingly somehow, then a minute later when I touched the casing of the iMac itself I got one hell of an electric shock from it. Ive checked the cable and mains socket, and the earth connection is fine, so thats not the problem. Later on in the day I got another shock from the keyboard. I would normally blame things like this on a static build up in me, but I didn't get shocks off anything else, just the computer. Its switched off for now just in case. Its the 24" model, and I think its still the latest version, got it just after leopard was released. Any ideas?