Settlers Rise of an empire crashes

So I installed Settlers Rise of an empire and now whenever I start the game it works fine up until the loading bar for the first campaign mission finishes loading. When it finishes loading I hear a split second of ingame sound and then the game crashes and I get the windows 7 dialog box that says the program has stopped working etc. Now the thing to keep in mind is that my computer was able to run settlers 7 but it was very laggy which is why I have downgraded to this settlers game instead. So if my computer can run the newer settlers game then I don't understand why it would not be able to run this one. Sorry for the extremely long description but I have tried reinstalling and all kinds of other fixes to no avail so I am desperate now please help.