Safe mode is an important troubleshooting tool. It boots the OS in such a way that it uses the bare minimum files and apps to start and run. This can help you isolate issues, figure out where problems ...

So my iMac has been a turd for the past 2 years. Graphic glitches and random lockups. I installed the Fan control software, and spun the fans up to top speed, and that helps (although it is LOUD now), ...