Selinima The last part is the easiest: it's called the infinite birth loop (or sometimes other names) and can be fixed with a mod from NRaas that has the initial W. The mod itself can't be discussed here because it contains features that technically raise the game's rating, but it's safe and reliable. And I don't know of another reliable way to fix this particular problem.
For the rest, can you confirm that all your content is loading in-game? Start another new save and filter in CAS or Build/Buy by pack to make sure the expansions and stuff packs are all present. What you've described can happen when an expansion is removed from an ongoing save.
If that's not the problem, load one of these older saves, go to Edit Town, evict the household, place them back in their house, and see whether you can play them.
Additionally, for now at least, delete the five cache files in your user folder each time you quit the game. They should be deleted regularly anyway, and frequently when you're troubleshooting, and also any time you add or remove a mod or some custom content. The files are in Documents > Electronic Arts > The Sims 3, and these are their names:
- CASPartCache.package
- compositorCache.package
- scriptCache.package
- simCompositorCache.package
- socialCache.package
Finally, let me know whether you use mods or are willing to add a few. If you already use some, please list them, except for the ones that contain adult conent; for those, you can list the creator.