My Note 4 doesn't start anymore - LED pulses blue

Hello everyone!

My Note 4 won't boot anymore.

It does shortly vibrate, the Blue LED light goes on and pulses. The display remains black.

Sometimes there are some grey stripes on the display (2-3 seconds) and then it goes dark again.

Here is a picture of how it looks like: https://ibb.co/fy3gjQ

I tried entering download and recovery more but it won't work.

When connected to a PC I can hear the Windows sound, that a new device has been connected, but nothing else happens.

I would be grateful for any idea. I have lots of pics and videos on the internal memory.

Thank you!