Unexpected error for Sims 3

It's possible you have corrupt saves or when you removed everything, the save had certain worlds or EP's so the save will no longer work unless you have those worlds and eps installed.  The saves could also be corrup if you had bad CC and you may not get waring that the saves are actually bad. Have you check your save folders for bad on the end of them and delete those. Have you tried clearing your 5 cashe package flies. It cleans the game without deleting anything and the package files regenerate themselves every time you play so you should clean those every time you play http://simswiki.info/wiki.php?title=Game_Help:Sims_3_Delete_Cache_Files

PS what kind of video card do you have? Sometimes a vidoe card can give out. Is your card updated?

How do you know what's bad on your save files? Also, I have never thought of clearing my cache files, but the link that you have there doesn't tell me what to do for Windows 8. Is it the same as Windows 7 would be? And honestly, I have no idea what a video card is......

Those 5 cashe files are located in the same place your saves folder is. This has noting to do with any version of Windows.  Your Documents, Electronic Arts folder to the sims 3 folder.  In the sims 3 folder you will find a save folder. That is where your saved games are. You click on that to see if you have any saves that are listed as bad. If you ever get a bad save error in game it will generate a bad file. The 5 cashe package files lited in above web are again in the same sims 3 folder in my documents. You can delete those 5 cashe files that state package next to them. After you delete them always check in recycle bin to make sure you delete the correct files just in case but those files will regenerate every time you delete them.

So I should delete the 5 cache files? Also, I don't see how you know that a saved file is "bad" will it literally say that? (Sorry if I'm sounding a bit unknowledgeable right now...)

Thats Ok and you can delete those 5 cashe package files every time before you start your game. It cleans it without deleteing anything from your game. Delete those files may take care of some glitches you might get in game. Where sims cant use the bed etc. Its always good to delete those files first with glitches before trying other trouble shooting ideas.

The save files at the end will have ".bad " at the end of the file. A normal save file will have.sims3 on the end. 

Ok, thank you. I will do that right now and let you know when I'm done. Thank you so much. :D

I have save files that have .backup are those okay? I also have 1 .bad save file

back up is fine its the ones that have bad you need to delete. Having those bad files could prevent your game from starting

You get back up files when you use the save option. There is also a "save as" option where you can rename the file so it does not overwright your old save. Using regular save overwrights old saves. I use "save as" so the saves dont overwrite each other. I always keep extra copies of my game just in case something goes wrong so I can get to older saves if I need to.

Where is the "save as" option? Also, do you really recommend using the "save as" option or is it just something to do if you want to be more cautious? 

save as just gives you a clean save everytime you use it. It does not overwirght the old save. When you overwright the save there is always that chance it wont save correctly and glich your game. In game when you you click on options menu in game just below "save" is "Save As"