I think a restore is the way to go. Whenever I suspect a virus or some other malware, I just restore the OS drive from Acronis disk images I make about once a month (I keep the last 2-3 images). Takes about 15 minutes or less. Even when Windows defender detected and "removed" a virus I had, it kept coming back. Once the restore from disk image was completed, no more virus.
I think it's a bit drastic, your solution, but it works.
in my case now I try to keep several restore points of windows. whenever I detect something, I just open panel control and restore the PC to a previous period of time.
using restore points instead of making a backup of the entire drive (as I think acronis do), is a lot faster (takes 30 secs to create a restore point) and I also have a pendrive with W8.1, if my computer does not boot or something, I just plug-in the pendrive and make a fresh install, no need of an external drive full of cloned ISO's of the Harddrive.