CAS Issues, Buy/Build Mode Issues, and Crashes...

Hello, I've been having trouble with the Sims 3 for about six months now. First, the screen would go black and the game would crash. After that problem ceased, an error message appeared while loading the game. I contacted EA and Windows, and had Windows go into my PC and try to help fix the problem. I updated my graphics card (AMD Radeon) and uninstalled and re-installed all of my expansion packs. Please help, I've put a lot of my time and money into the game. My PC runs Windows 8, I've never had a problem with running the game on it until now. 

Thanks!