XPS 15-9570, does not start anymore

Hello everybody,

my o.g. notebook does not start anymore. After switching on, the DELL logo appears, below it is that the drive C: is checked, which is terminated without error and the whole thing from the beginning.

With F12 diagnostics brings no errors. I could start a shell and look at the drives, that looked good (if you can tell).

The error occurred yesterday after a Dell update. However, I did not observe that, I started the update and went out to eat. After that it happened.

Before I reinstall win10 (is that possible?) I would be grateful for every tip.

Greetings Micha