I think from here on we may have to do things blindly...
Lets start with seus reinstall. ..,
I mean a complete reinstall... And also try to update your driver for k850...
If this doesn help... Then you have no option but to seek help of service centre...
Or else finally you can try kulenkendi....
They provide few patches without a penny...
Try it atleast... But i am not sure whether it will be a help or there is a help...