The version of The Sims 3 downloadable from Origin including its Packs uses EA's own tech and is compatible with Windows 10.
So if you are having problems, redeem your codes from disc versions on www.thesims3.com and download the Origin version.
Also try the following
- In the Search bar (bottom left) type: Internet Explorer
- Click the IE link
- Click the cog in the top right of the browser
- Select Internet Options
- On the GENERAL tab under BROWSING HISTORY click DELETE
- Make sure COOKIES AND WEBSITE DATA is selected and PRESERVE FAVORITES WEBSITE DATA is de-selected then click DELETE
- Run The Sims 3
Note: Deleting Internet Files from Edge, Chrome, Firefox, Safari, Opera will NOT suffice. It HAS to be Internet Explorer.
Also, create a The Sims 3 icon on your desktop, right click it and select RUN AS ADMINISTRATOR. Being an Admin on the PC is not the same as running a program as Administrator unless you disabled UAC in your Windows settings. If you don't know what UAC is, you didn't disable it.