Hi, I'm experiencing problems with my 3-year old 24" inch iMac aluminum. The first time he shut down, I was Skyping with my girlfriend. While working on it, it shuts down for no reasons. Sometimes it shuts down while browsing the internet, watching video on YouTube, sometimes just by going to the widgets. This is what I've done so far (these didn't fix the problem): - Booting in OS X from external HDD (verifying if it was HD related) - Replaced RAM with brand new ones - SMC reset, PRAM reset, VRAM.. - Several Apple Hardware Tests, short and extended for several hours (no problems found). Note that the iMac NEVER shut down while performing these tests. - Full clean install on the internal HDD itself - Performed Repair Disk and Disk Permissions - Created new user, logged in with that account (no luck either) - Checked the Power Cord for any damage AND switched to other wall sockets - Installed smcFanControl and turned the fans to full speed so it got cool enough (still shutting down) - Installed SystemLoad and performed those tests while monitoring the temperature with TemperatureMonitor. Check screenshot for the temperature values: http://dl.dropbox.com/u/42974675/Screenshot.jpg Hope anyone can help me try and fix this. I'm still a college student and need my computer for all my work. Besides, now my iMac is out of warranty, if i want to let them fix it, I'll have to pay a lot I guess Thanks a lot in advance! PS: If someone is experienced enough and kind enough to help me, I have saved the Console logs when he shuts down. Maybe someone can have a look at them to see the problem can be found there?