Downloaded a mod and now my games wont load

@sinPhilosophy 

You really can't hurt the game files by doing what you described you've done.  Even if you deleted a file in the main game files, a game repair should fix it.  And if it doesn't, you can start over fresh by uninstalling, then reinstalling the whole thing.  So, at worst case, it'll just cost you some time.  

Now to what you've described the game doing.  A bad mod can wreck a save.  Some mods attach data to the game's save files which remains even if the mod is removed.  More than likely, the save will eventually become corrupt and unplayable.  Corrupt saves can do a lot of things but mostly, they won't load properly and do what you've got going on or not load at all. It could be as little as one sim is messed up or one lot won't load or as big as the game just crashes when you try to do anything. 

So, in your case, I suggest:

1st, Run a game repair to repair any damage you might have done to the game files.  If the game starts and appears to run normally when you get it going, you should be all right.

2nd, Move the user folder - "The Sims 4" out of the Electronic Arts folder.  Or you could just delete it if you don't want to try to save your earlier saves, library, mods and CC.  Your choice.

Start a new game.  This will create a new user folder.  And you will go through the obligatory create and place a sim.  The either play on in the new save or save and exit.

If you want to see if your earlier save is good or corrupt, copy or move the saves folder from the old user folder to the new one.  Then start the game and load the save.  If it works, then exit without saving if you used any CC while you played it before.  If it doesn't work, it's corrupt and you should probably delete it. Afterwards, start the game and go through the create and place a sim again and save and a new saves folder will be created.

Once you've determined if the save is good and you want to keep it, then move your CC into the mods folder.  Start the game, load the save and make sure the CC is showing up as it's supposed to.  Again, exit without saving. 

Now it's time to test the mods.  1st thing, if you know or suspect which mod is the cause of your troubles, make sure you have the latest version.  Keep in mind that wherever you downloaded it from, may not be the latest version now since we've had 2 patches and a new pack in the last couple of weeks.  So, check on the status of any mods you use to make sure you've got the latest.  Once you have the latest, start putting them in 1 or 2 at a time and test them to make sure they work and not cause you any problems.  Just repeat until you've got everything in. 

At that point you should be good to go.

Hope this helps.