i would try to clean install win 10 before installing win 7 again (especially if you used your win 7 licence to upgrade to win 10, as if its over a month the win 7 licence is now a win 10 licence).
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/
Also, on another PC, download the
Windows 10 media creation tool and use it to make a win 10 installer on USB
After a broken reset, I would suggest a fresh install
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 screen asking for licence, click "I don't have a key" and win 10 will continue to install and reactivate once finished
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)