Question Samsung 840 EVO slow all of a sudden

[Maq___]

Hello,

my Samsung 840 Evo SSD became slow all of a sudden, it boots very slow, and I can't reinstall the Win 10 OS.

I am booting Ubuntu from an USB drive,
so please tell me how can I scan the SSD for errors and repair it,but from Ubuntu?

 

[rgd1101]

how full it is? ran health test on it?