shakira-teehee Bad custom content is a frequent cause of crashes, but it's not the only one. Another common cause is having a mod that depends on other content, for example NRaas Cupcake requires the Store Bakery set to be present, and the NRaas MasterController Progression add-on requires both the base MC and StoryProgression mods. If you do have MC Progression, or you have Cupcake and aren't sure whether the Bakery set is loading, remove the mod.
If that doesn't help or isn't relevant, please rename or remove the Sims 3 folder in Documents > Electronic Arts. When you open the launcher, a new folder will spawn with no content. Don't add anything to it yet; just see whether you can play like this. If it works, you can restore your old content, a little at a time.