Even if you haven't played on this computer yet, you could still have some issue in your new TS3 folder in Documents. Since you have no content yet, why not just trash the folder and try again with a new one? And just checking, but are you trying to launch the game while any of its folders are open? If so, restart your computer and make sure all windows are closed before attempting to load the game.
You could also try disabling your antivirus software's realtime scanning. Some programs have been known to interfere with the launching of TS3.
It would be useful to know the specs of your computer as well, so that you can get more specific advice.
I tried attaching the file you said to attached, not sure if it did.
@kittymew1234 A guess is the video chip (GTX 1050) may not (probably not) be in the game database and the game is crashing because of this. This is what I used to add my graphics chip to the database - link - Adding a new graphics chip to the Sims 3 database It is not as hard as it looks but if you never did anything like this before a little help would be nice. I recommend copying the two .sgr files to a safe location THEN editing the files so you can recover if you need to.
Ok so I looked into the adding the graphics chip one, but...it said to go into the Game folder and I checked to do that, my Game folder doesn't even exist! How is this possible? I bought the game, it's my Origin Library...
You could delete the Sims 3 folder in Documents by manually dragging it to the recycle bin; the game would be forced to spawn a new one the next time you tried to launch. There are plenty of causes of corruption in this folder, although it would be surprising if it was causing you problems before you ever had a chance to play. Still, one potential issue is that your currentgame folder could be corrupted. If you click on it and it won't open, that means the game can't open it either, which could cause the "serious error" message. (Side note: that folder should always be empty when you're not actually in-game, so if you ever do find files in there, you should delete them.)
Trashing your TS3 folder should get rid of a corrupt currentgame folder, but if that's not the problem, there's only one other potential solution I can find:
http://simswiki.info/wiki.php?title=Game_Help:A_Serious_Error_Has_Occurred
I think you tried unticking the "read only" box, but there's another fix to try at the bottom of the page, under "still not working?"
I honestly don't know how else you could try to fix this problem, other than editing the .sgr files as @roberta591 has mentioned. (I didn't have to do this, and I wouldn't know where to start, either. At this point, I myself would probably go through the whole process of uninstalling, cleaning the registry with a tool like Piriform's CCleaner (free), and reinstalling from scratch, but editing the .sgr files is certainly worth a shot. You can probably find them here: C:\Program Files (x86)\Origin Games\The Sims 3\Game\Bin but that will depend on where you told Origin to install TS3. Regardless, you're looking for a file within an application's folders, not anything in Documents.
