MPB shuts down shortly after turning on, halfway trough the status bar

My MBP has been working fine for years now. There was no change, dammage or anything else done to it. Updates were done regularly. All of a sudden, shortly after turning the MBP on, it would shut itself down halfway through the status bar, everytime i try.

After a long research on the web, no answers. Going to an "Apple Authorized Service Provider" they went trough everything, but starting up in "Apple Harware Test" and also in "safe mode", showed no sign of problems. NO answers there.

I tried to get hold of my latest data, and by chance i found out, that by holding letter "D" constantly from starting up, the MBP would not shut itself down, but run just normal, no safe mode, no harware test, just normal. I could backup all data and restore the MBP to factory settings (while holding letter "D" all the time).

Despite everything, unless i keep holding letter "D", MPB shuts itself down.

Any help?