Hi guys, I recently downloaded Sims 3 pets onto my computer to get back into Simming. I got an error message, it suggested uninstalling. So I uninstalled the base game and pets, and reinstalled. I still get the error message. Both games work fine on my laptop.
The message I get is:

"C:\Program Files\Electronic Arts\The Sims 3\Game\Bin\Sims3Launcher.exe
The application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem."
The launcher won't come up at all, I've tried opening the .exe file itself to bypass the launcher but I get the same message.
Any ideas?

• Sims 3 - Installing / Patching / Uninstalling
  1. Whether you are Installing for the first time or Reinstalling, be sure to read the Game Help:Install^wiki FAQ.
     -
  2. This Game_Help:TS3_Uninstall^wiki link has the step-by-step instructions to guide you through uninstalling The Sims 3,
     and its (EP/SP) packs. As well as removing any leftovers after uninstalling.
     -
  3. The Game_Help:TS3_Patching^wiki Guide provides information on:
     • Tips Before You Begin
     • Patching Common Errors
     • Manual patch Downloads
     • Invalid File Errors and more
  
  

Downloaded Sims 3 Pets from where? Could it be a corrupt download? Have you tried redownloading?

Which .exe do you use to bypass the Launcher? Game Help:TS3 Bypassing the Launcher^wiki

Sims3Launcher should be the Sims3LauncherW.exe

Game Help:Patch_Table^wiki
And what patch version is the base game on? Did you patch via Launcher or manually? Prompted to patch by the Pets install or patched separately before installing Pets?

Have you done as the error suggested and reinstall? Preferably after a FULL and clean Uninstall as shown in the Uninstall FAQ.

ps: and welcome to MTS, TrifleDisaster!