Having tremendous troubles with the Sims 3... [SOLVED]

Hello. Sorry, I'm very new to the Games4theworld forums and I don't really know where to post this, so I apologise if it's the wrong place.
My Sims 3 is giving me such a headache! I have the base game, World adventures (Origin digital download), Ambitions (Disk), Late Night (Disk), Supernatural (G4TW download), Seasons (Disk), and University Life (G4TW Download). I have to use the seasons disk, but its running university life. Up until this morning it was working fine. And then I downloaded the ultimate fix, and I probably did something horribly wrong, because the launcher kept loading with this problem: 'The Sims Launcher has stopped working'. So, after being unable to find any solution, I completely uninstalled everything. I did not however, look at the registry editor after uninstalling (Is that the problem?).
Anyway, I reinstalled everything in order, and downloaded the latest patch (1.55) before all the expansion packs. It all went on fine. Then, I opened the launcher, and lo and behold I get a different error message: 'There was an error during startup. Please see the log for more details'.
Only THEN did I check the registry, but there weren't any extra files, only the files for the expansion packs and base game I had.
I have mods, but they are up to date, all of them.
I have custom content, but when I uninstalled Sims 3 it asked if I wanted to store save games, custom music and custom content for when I reinstalled. I clicked yes.
BTW (Just remembered this) when I finished installing the patch 1.55, the launcher was working fine. I didn't check it again until I had finished installing everything. I have an ever so slight inkling that it is the whole 'University Life without the proper disk' thing that's causing the troubles, however I'm not sure as I've never had such problems before, and therefore thought it better to ask some experts.
I'm really sorry that this is so long, but I thought you would want to know in as much detail as possible. This whole incident has brought me to the brink of insanity and I really hope somebody knows what the problem is.
Thank you for your time.

Ok. So right now, everything is installed?
Before applying the Ultimate Fix, can you open your Launcher?
Is your base game Origin digital download as well?

Yes, everything is installed. I have not downloaded the ultimate fix yet, and the launcher does not open. No, sorry for not saying, the bade game is from a disk.

Please try to run the Launcher as Administrator, from the folder C:\Program Files(x86)\Electronic Arts\The Sims 3\Game\Bin.
Right-click on the Sims3Launcher.exe or the Sims3LauncherW.exe (try both) and click on "Run as administrator".
Does it help? What happens?

I tried both, however neither of them worked, both coming up with the same message: 'There was an error during startup. Please see the log for more details'.

Ok. I have an idea. I think the saved stuff you did while re installing might be the problem.
Can you give us a screenshot of Documents\Electronic Arts please?

Here you go!

Ok, try renaming that folder "The Sims 3", and relaunch the Launcher.
If you're ok with loosing your saved games and CC, delete the folder completely!

I renamed it 'The Sims 3' and launched the launcher. It did nothing to improve the current issues. Also, I'm not particularly willing to lose my save games, as there is some important stuff in there (Well, I think so) that I've been working on for a while. Any other ideas?

You will not lose it if you rename it. Please rename it to "The Sims 3_" and try opening the launcher again...

hmm. Renaming it to 'The Sims 3_' didn't work either. Again, the message 'error during startup etc' came up again. And it just kept creating another folder named 'The Sims 3' in the same place (documents\Electronic Arts) which is empty, and I don't know why...

Hello? Can anybody help me? I'm really confused and I just want to play a game. Why is that so hard?

Sorry, was at the cinema!
So, even with renaming the folder, you can't open the Launcher?? That's weird.
If so, your game is totally corrupt and the only way would be to do a clean uninstal, delete everything in Documents\Electronic Arts and restart your pc. Then re install everything. You will lose everything but you will be able to play...

I suppose that's all I can do... Thanks for all your help. And I hope you enjoyed the cinema! 

Yep. Superman was nice.
Sorry I can't help you more...
Tell us how it went!

Hi again Shamrock!
So I completely uninstalled everything (and I mean everything this time: custom music, custom content etc.) but kept my save file by moving it to desktop. I then reinstalled everything again, moved the save file back to where it should have gone, redownloaded all my mods, downloaded the ultimate fix, and hey presto! The game is working like a dream again. And, I still have all of my saved games, including my big project, so that's a plus. Admittedly there's some custom content I couldn't track down again and so had to go on without, but that's a small price to pay for getting the game working again.
Thank you for all your help, and I'm so glad my game is working again! 

Sure, no problem! Glad it worked!
That CC you left out was probably the source of your problems and was conflicting with the game...
Anything else we can help you with?

Not at the moment, but thanks for asking. Undoubtedly as my game gets older, more problems will arise, so I will certainly be back someday. Probably soon.

Ok then. I will close this topic. If any other problem appear, please open a new one!