Hello This morning my iMac stopped working. I had Safari, Mail and uTorrent open. It was on for about 5 days already without going to sleep/snooze. Suddenly it freezes and all I saw was the Safari window but nothing on the keyboard worked, even not after unplugging and plugging back in. I could still move the mouse but when clicking on something it didn't do anything. I waited a couple of hours and tried again but it didn't help. What was remarkable was that the screen wasn't locked. The screen was black and when I moved the mouse the Safari window appeared again but I didn't have to log on what I normally must do. I tried different key combinations but nothing helped. So I kept on pushing the power button until it shut down. After a few seconds I started the iMac again and I got a message that the Mac was shut down in a wrong way and it asked me to restore the open applications which I did. Then I quit all applications and shut the iMac down as it should. Everything went normally this time. What should I do now? Do I need to do some cleaning or maintenance on it? It's a fresh install from about two months ago, can there be something wrong with my system? How can I know what was the cause of the freeze? EDIT: I installed a Samsung EVO 850 SSD two weeks ago but I haven't had any troubles up until now so I don't think this is the cause. Thanks!