I recently installed 'Monkey bars' and it turned my neighborhood a dark red.
I updated my graphics drivers, and reinstalled Sims 3, and nothing has helped. I've also tried uninstalling and reinstalling Monkey bars, and that didn't help either. I'm really desperate for help.

If you have any idea how to fix this, I'd really appreciate it.

Thanks.

Monkey Bars wouldn't have done that. It -can't- do that. All it does is create a couple of folders and a file that would not affect in-game graphics whatsoever. But in any case, it is completely unnecessary to use anymore, as custom content does not go in Program Files anymore.

Please post the summary version (using the template) of your system specs: Game Help:System Specs^wiki

==System==

* Operating System: Windows 7 Home Premium 64-bit
* System Manufacturer: System manufacturer
* System Model: System Product Name
* Processor: Intel(R) Core(TM) i5 CPU
* Memory: 4096MB RAM
* Page File: 1456MB used, 6729MB available
* DirectX Version: DirectX 11

==Display==

* Name: NVIDIA GeForce GTX 460
* Manufacturer: NVIDIA
* Chip Type: GeForce GTX 460
* Approx. Total Memory: 2529 MB

* Main Driver: nvd3dumx.dll,nvwgf2umx.dll,nvwgf2umx.dll,nvd3dum,nvwgf2um,nvwgf2um
* Version: 8.17.12.6658
* Driver Date: 1/7/2011 21:27:00

==Sound==

* Description: Speakers (High Definition Audio Device)
* Driver Name: HdAudio.sys
* Driver Version: 6.01.7600.16385
* Date: 7/13/2009 18:07:00

==Disk & DVD/CD-ROM Drives==

* Drive: C
* Free Space: 694.1 GB
* Total Space: 953.8 GB
* File System: NTFS
* Model: WDC WD1002FAEX-00Z3A0 ATA Device

I think it may actually be the Graphics card.
I reinstalled again, and got and Unrecognizable Graphics card Error.
I checked the box, and GeForce GTX 460 wasn't on there. Perhaps because it's newer than the game itself?
I really don't know. I also tired updating DirectX. That still didn't help.
But what I don't understand is that it worked completely fine for over a week...

• Sims 3 - Uninstall
  This Game_Help:TS3_Uninstall^wiki link has the step-by-step instructions to guide you through uninstalling The Sims 3, and its packs (EP/SP).
  
  If you're reinstalling because you're reverting to an older patch, or just do not want to use the Launcher/EADM to patch, read this FAQ Game_Help:TS3_Patching^wiki once through before patching and then follow the guide.
  
  

What prompted the need to install Monkey Bars?
Well, other than Monkey Bars, what else did you add this week? Any changes to the PC or game other than Monkey Bars?

The few causes of this that I've seen are

1. unsupported hardware
2. outdated drivers/directx
3. outdated precomp file (the old nude censor fix)
4. corrupted game resource.cfg (not the one used for CC framework)
5. other corrupted game files or a simple corrupted install

Some threads that I've compiled in one post are here: https://modthesims.info/showthread.php?t=382075.

Your GPU is fine, I have the same model, and yes that notice at the start of launching the game is annoying but I only get it once every new install.

Now, since we can rule out [1] and [2], then working down the list,
[3] don't install CC that are not in the 3 standard file formats (.Sim3Pack, .package, .Sim)

[4] have you messed with the wrong resource.cfg in an attempt to get CC in game?
You're sure you had installed Monkey Bars instead of Monkey Helper (perhaps you had the old installer as the download is no longer available)?

[5] Else, my only other suggestion is a reinstall as that leaves corrupted game files.
You may want to try uninstalling the last EP you have first before going through the whole procedure from scratch, but if that fails, then no choice but uninstall and reinstall everything. When you did that once before, did you follow our guide?

The old Mod Manager program also caused this, but I believe (?) its been taken down now.

Nothing else has been added to the computer recently. When installing CC I always check to make sure its in the right format.
I uninstalled the game following the guide and completely removed sims from my computer.
Reinstalled, and it's FIXED!

Thank you so much for all your help! :D