all of a sudden : system crash and cannot be restored

i use my pico for 3 months. Today, I saw that browsers freeze a lot and icons in ubuntu disappear.

I decide to force reboot but nothing happens. When I launch a soft reset, I saw the bios. I tried to restart but I saw bios again and again.

At the moment, I can't boot normally. If I save config in bios and go to reboot, screen go to bios again in 2 seconds later.

I have no solution.

Could you help me please ?

Thank you