Note to self: Never use Easeus Partition Manager to resize the Windows partition.
It totally borked the boot record, beyond the point of repair tools. Even manual recovery commands failed.
Wiping and starting over. I was due for that anyway. 
Fortunately, I have everything on separate partitions/disks so while I have to reinstall the OS and all of my apps, I have all of my data intact because of daily backups.
Get bent, Cortana.
Back up and running, basic apps all loaded and working. Yay, backups!
@voltronic in the days of NVMe's I just swap disks if I need another OS, it is the only sane way.
@voltronic clone would be the way but don't ask me how to do so from Windoze );
@matuzalem
Macrium Reflect is what I've used in the past. Clonezilla is also great, which is the modern equivalent of the old Norton Ghost that I used often in my PC repair shop days.
@voltronic norton was the last thing I used to clone windows on PC then I managed a dual boot (windows/mac) lab with Deploy Studio (and Munki) those where the days!
@matuzalem
What do you do, clone everything through a second NVMe?
Otherwise I'd think you're still reinstalling apps and such.