Well, I guess I must add to this thread.
I'm having the same problem with my Sims 3 game on my husbands PC (thankfully not on the laptop which is where I play most of my Sims and my challenges). I started the game up 2 days ago after not having played on the PC since March. Everything was great until I installed Ambitions. Then it decided after about 15 seconds (real time) to just die. No explanations. Just a black screen and then the desktop. Nice. Went through all the checks, same thing. Uninstalled, reinstalled all 4, same thing.
Found this thread and read through it. Got my husband's computer science brain involved. Followed Frey's instructions from July 19 to the letter. I did change one thing though. After talking it through with the computer brain, we thought that since the expansion CDs include the patches from the last one, updating through the launcher after each installation was redundant and perhaps that was the problem.
Last night we did the computer clean-up and this morning I installed the base game. Opened the launcher, said no to updating, and opened the game. Works perfectly! Victory #1. Then I exited the game without saving and installed WA, updating when the installer told me I had to. Again, opened the launcher, said no to updating and ran the game. Works again! Victory #2. On to High-End Loft Stuff. Same process, same outcome. Victory #3! Ambitions proved the sticking point. Again I said no to updating from the launcher and just went in to play the game. 15 seconds later, black screen and desktop. Aarghh! I then updated Ambitions through the launcher just to see if it would help. It didn't.
So I uninstalled Ambitions, but now HELS claims the black screen and dies. So, at the moment, I have reinstalled Ambitions and will wait patiently until the hubby comes home from work in 3 hours to see if he has anymore ideas.
If anyone else has any ideas please don't hold back, I've run out. Other than uninstalling everything, again.