If no internet solutions have worked for you, it's possible this error is due to problems with your Windows account and start-up process. We actually wrote a troubleshooting guide for this today which can be read Link Removed. For some reason, the "critical start menu error" is getting more common now and our solution seemed to help with most of these issues. Just follow the steps on how to restart your application identity service and hopefully you won't have to go through the pain of re-installing.