jeffle9423 Please try installing one item into a clean user folder, through the Store website rather than the in-game Downloads Dashboard. Move the Sims 3 folder out of Documents > Electronic Arts and onto your desktop; if the folder copies instead of moving, or you get an error when trying to move it, stop here and let me know.
Otherwise, open the launcher to spawn a clean folder, go to the Store site, sign in, open Store > My Store Account > Purchase History, and try installing one small item. If it appears to install correctly, launch the game, start a new save, and confirm that the item appears. If it does, install the rest of your content, a few items at a time.
Your saves and other user data won't be available because you moved the folder that contained them, but you can restore them after you've finished installing your Store stuff. For more help rebuilding your user folder, please see this post:
[Read First] Sims 3 Store guide | EA Forums - 11157679