Crashing, computer freezing, monitors shutting down on startup

Okay, so I am not sure if I am posting this in the right section, but I have a really serious problem. Before I get to that, I will have to give you a brief history of my recent events.

So, last week I think, I downloaded the base game and 2 expansions from here (pets and seasons). Now, for a while I have been having issues with massive lag and FPS spikes that most people are having, which makes the game unplayable most of the time, even though I have a machine that is more than powerful enough to run the game on the highest settings. So, last week, I tried installing it again. I kept trying so hard to get the lag to stop or at least lower it enough to be able to play. I tried capping the game at 60 fps and playing in windowed mode in order to lower the lag and the tearing, I messed around with the settings through my AMD graphics options. For a while it worked and then something crazy happened. 
I tried starting the game and I get to the black screen with the logo. Now, afterwards I expect to the see the cut scene before being greeted by a loading screen but that never happens. In stead I end up stuck on a black screen, no sound, no cut scene, no nothing, my whole computer freezes up (no alt+tab, no task manager, nothing works). So I restart my computer, my monitors shut down as a normal part of the restart, but they never turn on again! In stead, I am forced to forcefully turn off my computer and then start it up again in order for my monitors to turn on (i have 2 of them). This happened several times, I could not start the game nor play, so I uninstalled. 

Now, today, I bought the base game. I found it for just a couple of dollars online and decided to get it and try again. So, now I have just the BASE game through origin. I install it, start it up, and again, the same problem! I deleted the old folder from my Documents folder (i reset the settings), restarted the settings and stuff, but the game won't start up! My computer keeps freezing and my monitors shutting down! What on earth is happening to this game! xD I don't even know what I did to make the game not playable at all now! I need help, otherwise, well my money is going down the toilet. 

As reminder, my computer exceeds the requirements, I am up to date with my drivers, the game worked before (although it lagged and stuff) and I am using the original base game without any expansions. 

Okay, so I feel really dumb right now. Resetting the AMD settings did the trick. The game turns on normally, but I cannot figure out how the hell it didn't occur to me to do that in the first place. *facepalm* 
Anyway I am still experiencing some lag, which is a shame, but I will look into that other section that you pointed out.  Thanks a bunch!