I had come across many instances where pc is not able to boot in normal mode as well as in safe mode. Just get a blue screen which appears to be desktop background with mouse pointer (which can be moved around). However, there is no desktop icons and if the computer has windows password the login screen doesn't appear. So this is happening before pc ask for login. On dell computers we can go to recovery options but it doesn't give any option to use any recovery tool and give the same screen. We can't access task manager or ease of access on that blue screen with any of the key combinations. One common thing in all the issues that it usually happen after windows update. However it is not easy to diagnose which update it will be as pc doesn't boot up and there is no option for doing a system restore.