On another PC, download the
Windows 10 media creation tool and use it to make a win 10 installer on USB - just a boot disk
change boot order so USB is first, hdd second
boot from installer
on screen after languages, choose repair this pc, not install.
choose troubleshoot
choose advanced
choose start up repair - this will scan PC and maybe fix this - will ask for logon info
if that doesn't help, try going into safe mode;
boot from installer, on 2nd screen after languages, choose repair this pc, not install
choose troubleshoot
choose advanced
choose start up options
hit the restart button
choose a safe mode (it doesn't matter which) by using number associated with it.
Pc will restart and load safe mode
sometimes just going into safe mode can be enough, restart PC and see if its better