I have reinstalled my NVIDIA drivers, installed the latest DirectX, i have also renamed retailclient folder and repaired everything.
But i am still getting the Error C7.
In addition, i was able to play since Early Access, until pre 1.2. Just got back from travelling and wanted to try 1.2 and could not play. I dont think its my system, i5 with 8gb ram and gtx560 TI.