Help laptop (Toshiba) does not want anymore?

Is my laptop broken, how is it there or can you save something or because of a laptop?

Not broken directly.

Your windows is seemingly damaged.

Do you know how I could fix that? Have a presentation in 4 days and have to do that over the computer

Do you still have a stick / CD with a Windows 10 installation on it?
I would plug in the cd or the stick and fix booting and windows.
In the worst case, I would save the hard disk via Linux (LiveCD) to another disk and then reinstall Windows 10 completely.

With the Recovery CD

https://www.lifewire.com/how-to-rebuild-the-bcd-in-windows-2624508