Can't boot from anything after restoring old BCD

#1
brand new build, AsRock Z97m motherboard, running win 7 64bit (UEFI mode) off an SSD.

I was trying to fix a blackscreen-on-restart issue (which I now think was a dodgy graphics card) and following some suggestion on another forum, I tried repairing the BCD with easyBCD, and added win 7 as the sole boot option as suggested by the program.
Next restart, windows said there were errors/missing entries in the boot directory, and began automatically fixing them.

After that I couldn’t boot into windows but could boot from USBs. Repair tools from the USB bootable windows iso did nothing.

Updating BIOS, unexpectedly, allowed me to boot into windows again from the SSD, but I still couldn’t boot from DVDs, and USBs would only work once. I could boot from a USB the first time I plugged it in and then the next time would give the 0xc000000e error. If I used a new USB stick I would get another one chance to boot from USB.


So I decided to restore my old boot settings using the backup EasyBCD had made before the “repair”.
This completed “successfully”, and from the next boot onwards I can’t boot from any source at all.

Symptoms when I boot (all options show AsRock splash screen fine, then this):

[TABLE="class: grid, width: 800"]
[TR]
[TD]From windows boot manager[/TD]
[TD]OS Selection screen with windows 7 as the only option. Selecting windows 7 leads to black screen, keyboard turns off, mouse still on but no cursor or anything.[/TD]
[/TR]
[TR]
[TD]From hard drive directly[/TD]
[TD]“reboot and select proper boot device” screen[/TD]
[/TR]
[TR]
[TD]From CD/DVD drive[/TD]
[TD]“reboot and select proper boot device” screen[/TD]
[/TR]
[TR]
[TD]From USB (non-UEFI mode)[/TD]
[TD]error 0xc000000e: The boot selection failed because a required device is inaccessible.[/TD]
[/TR]
[TR]
[TD]From USB (UEFI mode)[/TD]
[TD]boots straight to BIOS options screen[/TD]
[/TR]
[/TABLE]


Stuff I’ve tried so far:
[TABLE="class: grid, width: 800"]
[TR]
[TD="bgcolor: #efefef"]Solution attempt[/TD]
[TD="bgcolor: #efefef"]Result[/TD]
[/TR]
[TR]
[TD]“Load UEFI defaults” in BIOS (sets windows boot manager to the top of the screen)[/TD]
[TD]No change[/TD]
[/TR]
[TR]
[TD]Clear CMOS using jumper[/TD]
[TD]No change[/TD]
[/TR]
[TR]
[TD]Boot with SSD unplugged[/TD]
[TD]“Reboot and select proper boot device” again, this is with only the DVD drive available as a boot option. No UEFI option for the DVD drive, interestingly, even though it has the Win7 install DVD in it and when the computer was working properly there were two DVD drive boot options, UEFI and plain.[/TD]
[/TR]
[TR]
[TD]Remove CMOS battery and replace[/TD]
[TD]Still same error: booting from USB gives 0xc000000e error, booting from DVD gives “reboot and select proper boot device”.[/TD]
[/TR]
[/TABLE]




Does anyone have any suggestions? I'm feeling pretty out of my depth here and dunno what else I can try. Any help would be hugely appreciated.