No Boot after Win10 Fall Update

[Theorak]

Hello, I'm having troubles booting my PC since the Fall Update at the start of August, the outcome is:

- normal boot ends at ASUS (motherboard is ASUS Z170-K) loading screen

- after failing to boot 2 times, 3rd booting process will attempt to 'automatic repair' but also feels stuck with no drive activity after 15 minutes

- booting to repair USB drive does gets stuck when choosing 'repair options' (new installation might work from here, but I would rather enter the system for backups first)

- in all booting processes, the primary screen UWHD via HDMI is ignored, only the second screen via DVI is showing something, both are connected to the graphics card (internal card only usable when removing external, no matter iGPU settings)

 

how the issue persists:

- had new GPU installed, Radeon R9 280X (died) to nVidia GTX 970, and new drivers installed

- right after that, the Fall Update happened and the issues first came up, but after a few rounds of turning off and on again, the update was sucessfully installed and all ran well for a few days

- I uninstalled the old AMD drivers now and the issues came back, but this time with no successful boot in sight

 

rest of the system:

Case	Phanteks Enthoo Pro
Mainboard	ASUS Z170-K
CPU	Intel Core i5-6600K Tray
Heatsink	EKL Alpenföhn Brocken 2 PCGH
GPU	Club 3D Radeon R9 280X
RAM	Kingston HyperX Fury 16GB Kit DDR4-2133 CL14
Storage	Samsung 850 Evo-Series 500GB
PSU	Cougar GX600 600W

 

I'm hoping for some tipa as to how I could enter my system one more time, to make a few backups, so I can have a fresh install for stability.

[Origami Cactus]

Pull out the drives, put them into some working system, do your backups, then reinstall windows.

 

Option 2: make a bootable linux usb stick, boot into linux, make your backups, then reinstall windows.

[Theorak]

Reasonable approach, thank you.

I've prepared a Windows an Linux boot stick and did backups.

Got another repaired start with the Windows drive, I can properly backup from here and will reinstall soon.

 

That should resolve it.