Hi, I am Dave, I will help you with this.
1
Can you not get into the Recovery Environment using these steps?
Start your PC, just as Windows attempts to load (spinning dots), press and hold Power Button for 5 - 10 seconds to perform a Hard Shut Down
Do this twice
On the third start Windows will boot into the Recovery Environment and from there you can access System Repair, Safe Mode, Command Prompt... etc.
2
If you are trying to boot from a Windows USB and you are still getting a BSOD, then that indicates your system is either not booting from the USB or the USB is corrupt or there is a hardware problem, because you should never get BSOD's when booting from a USB.
What method did you use to create the bootable USB, and what changes did you make in your BIOS to enable USB booting?