how can i resist a doggy bumping a thread...
On another pc, download win 10 installer USB or DVD from here:
win 10 media creation tool
change boot order of old pc so USB or DVD firsh, hdd second
boot from installer
on screen after language choices, select repair this pc, not install
select troubleshoot
select advanced
select start up repair - this scans pc and tries to fix boot - will ask for logon details
next step if that doesn't work is boot from installer again, select repair again
Slect troubleshoot
select advanced
select start up options
choose one of 3 safe modes
pc reboots into safe mode.
restart pc (yes, you did nothing but this has been known to fix it before)
if neither of these work, I would suggest a reset
now first, if there anything on pc you want to save, either put your hdd in another pc and copy files over or try this: http://www.howtogeek.com/howto/windows-vista/use-ubuntu-live-cd-to-backup-files-from-your-dead-windows-computer/
d/c all extra hard drives as a reset will delete their contents if left attached.
now once you saved everything, boot from installer again, select repair pc again,
now select reset on this screen
two options, save files and settings, or wipe it all. If you haven't been able to save anything off pc, I would choose save files. If you backed it all up, its your choice here... it is anyway, I just offer hints
Either choice you will lose all your programs
which ever you do, windows will save a few things and then restart pc to reinstall win 10
hopefullt that will fix it.