Windows 10 can't boot up or in safe mode

[Swimmingly]

Can't boot up windows 10 after trying to install custom windows theme. Error says Microsoft visual c++ runtime library runtime error logonui.exe.

 

[Colif]

On another PC, download the Windows 10 media creation tool and use it to make a win 10 installer on USB << just a boot drive

that file could be a problem as it might stop you logging in
we can try to get into safe mode though unsure how to fix it from there
change boot order so USB is first, hdd second
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

if you can get to safe mode, we can try to run System file checker and it might fix it
open command prompt (admin)
type SFC /scannow and press enter
once its finished, restart PC and see if its fixed (only do this if it fixes things - if it finds nothing wrong it might be pointless restarting)


if safe mode doesn't work, as sometimes the Start up options screen isn't available, try a start up repair which is on same menu
another choice is system restore which is also on the troubleshoot menu. If you lucky there is a recent date here and you can roll system settings back to before the theme was installed.

if these options don't help, try making this on another PC: http://www.howtogeek.com/howto/windows-vista/use-ubuntu-live-cd-to-backup-files-from-your-dead-windows-computer/ and use it copy things off C you want to rescue