Hey, I just switched to my first mac a couple weeks ago. Everything was working fine until tonight. I was just using firefox, listening to itunes, nothing too intensive (especially for a powermac) when all of a sudden everything just crashes hard. The dock froze up, i tried to force quit all my applications but that didnt fix anything. Then my screen went black and the fans started spinning up so loud i thought it was going to explode. Its back up now, but does anyone have any advice on what i did wrong, or how to safely get out of a situation like that if it happens again?? BTW im running 10.4.3 as of two days ago.