When I edit the sims in a household the game reverts to the Origin screen and doesn't save the changes or the game. I have tried asking the sim to "move in together" but the same thing happens.
You mean the game crashes ?
Could you post your Computer's DxDiag?
To gather a DxDiag on your computer, please follow the steps here: http://answers.ea.com/t5/The-Sims-3/HOW-TO-DxDiag-for-Sims-3-PC-Only/td-p/1049584/
Please either use pastebin.com and put the link here or use spoiler tags.