This old hdd, was it an install from another build? win 10 is pretty good at moving but even its not perfect.
You might be better doing a fresh install
On another PC, download the
Windows 10 media creation tool and use it to make a win 10 installer on USB
is there anything on C drive you want to rescue? 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/
change boot order in BIOS so USB is first, hdd second
boot from installer
follow this guide:
http://www.tenforums.com/tutorials/1950-windows-10-clean-install.html
when you reach the screen asking for licence, click "I don't have a key" and win 10 will continue to install and might reactivate after install, but you might have to contact MS via settings/update & security/activation - look in bottom of right column for contact details), If you explain what you did, and know previous licence key/email address, they should tfr activation
On the screen where you choose where to install win 10, if it gives you an error about GPT drives, delete all the partitions on the hdd and press next. If it still gives error, cancel out of the installer and restart PC and start installer again, it will accept next on that screen this time (some PC just need a restart here)