I've made it to the freshman party at Edmund Hall where I need to recruit students for the experiment. Up to this point I had hardly any problems. Now the game crashes frequently - the error being "Game.exe does not work". I've tried running the game as admin, tried Windows XP compability setting, tried restarting the computer and de-installing/ re-installing to no avail.
I'm running Windows 7 64 bit, AMD Radeon HD 6570, Direct X 11. All drivers are up to date and all minimum and/ or recommended requirements are met, at least as far as I know. I disabled my firewall and other programs that might interfere except the antivirus where I added the game.exe file to the trusted files. My desktop graphics are set to basic and the game's graphic settings are set to default, that is low to medium. Does anyone have an idea what else I could try?

That's pretty much all you can do. Btw, the game doesn't use the DirectX11 components but the old DirectX9. Some of those components are missing on Win 7 by default, but if that would be the cause of your problem the game hadn't even started. However, it doesn't hurt to explicitly complete your system with these older parts of DirectX.
http://www.microsoft.com/en-us/download/details.aspx?id=8109
Download and run the file from Microsoft. Extract the content to a separate folder, then go there and run DXSETUP.exe for installation.

If you're using a multi-core system, you could try forcing the game to only use one core. Start the game and Alt-Tab out of it. Open the Taskmanager (Ctrl+Shit+Esc) and on the Processes tab search for the game's running process.
Right-click it and use the Affinity option to uncheck all cores but one. Now go back to the game.
This setting isn't persistent and must be repeated every time you start the game.

The game has also some issues when saving in closeup views. Don't do that. Only save in regular locations where you can see your character. When the game always crashes at the same point, you can use an older save and do things in a different order or go to another location, try to advance further, then save and only after that go to the critical area that used to crash.