OwedEvil liked a post in a topic by Aviat0r in Suddenly game wont start.
Reinstalling is an option, of course. But beforehand you should try to make a clean reboot of your PC. Not shutting down and starting again, but making a real reboot.
OwedEvil liked a post in a topic by Kubik in Sudden bad stutter
based on your description I would more likely guess ti to be an network issue. But what I can say for sure is that it have nothing to do with .net, because game itself does not use .net.