Installing expansion packs to D: drive...???

I've been reading the threads, but can't seem to figure out what I'm doing wrong when installing the expansion packs. 
The base game works fine on D: but when I go to choose the place for the expansion packs it defaults back to C: and when I change it to D: I'm not sure where to put it. Just on the plain D: it says "already installed the sims 3", and when I put it in D:/Game it installs but won't run..the error message says "error at startup, check the log". I watched your video and there are no extra expansion packs in the Wow...SIMS3 folder. Another thread also said don't install Origin, so I didn't this time but it's still not working. I'm at a loss...

I keep seeing things about copying and pasting files, I haven't done any of that, not sure where and what to copy to or from where. Maybe that's the problem?? HELP, 
Erin

//EDIT

Hello???? Anybody? What's the deal with the SKU? Do I need to change it?

Helper Edit: Please do not "bump" topics (Bumping topics is against the forum rules). Helpers are all volunteering for this, and are not obliged to help you folks. Impatience won't help anything.

-J.T.

Hello,

When you install the game/s, be sure to select 'Custom' installation. There's a screen that'll say "C:/Program Files/Electronic Arts/The Sims 3". Just click the 'Change' button and point it to where you want to install.

You should probably make subfolders under (example):
D:\Electronic Arts\The Sims 3.

The full path would look something like (example): 
D:\Electronic Arts\The Sims 3\World Adventures.


So in other words, all sub-folders are an EXTENSION of the original \Electronic Arts\The Sims 3.
Hope that helps.  

i did that already. 

Just to clarify, the error you've got is "The sims 3 is already installed" and "Error During Startup" right?

yes.

Since you've got several errors, I think you should do a clean re-install.

To do a clean re-install (I emphasise "clean" because it's very important and vital):

1. Download and install Your Uninstaller Pro from www.games4theworld.org.
2. Choose "The Sims 3" and click the button "Uninstall" when the panel of Your Uninstaller Pro has popped up.
3. Choose Super Mode and click "Next".
4. Wait for it to uninstall the base game.
5. The uninstallation wizard may ask you to restart your pc. Choose the alternative instead.
6. Wait for Your Uninstaller Pro to scan for leftovers and remaining registry.
7. If the Uninstaller found any, select all and delete them all.
8. Restart your pc.

Once you have done that, download and install CC Cleaner. Use the registry cleaner included in the CC Cleaner and scan for and fix all the issues. And then you can proceed to re-installation.