Windows 10: Windows 8.1 does not boot, how to fix it thru the cmd x:/sources

I have an ssd with Windows 8.1 pro installed on it, something has gone wrong and it does not boot anymore. In the BIOS it is listed as a drive, but not in the boot priority, so I guess the MBR is damaged ?.On the same pc I have an older XP, and it does boot ok, when in XP I can see the ssd drive, these are the details:C:/ XPE:/ XP's second partitionG:/ I believe 8.1 stuff as I see two directories "snapshots" and ""temp" in temp there are files like bcdinfo.txt, bootfailure.txt, disklayout.txt, SrtTrail.txt, and SrtTrail.logH:/ 8.1 I can access the data on the H ssd, I can read/write on

:)

 

HP - Windows 10 - X:\sources>bootrec/fixboot ---> Access is denied.

My wife's computer has crashed and will not reboot.

She gets a blue screen that has the error code 0xc0000034

I've tried following some steps I found online - How to Fix a 'Boot Configuration Data File is Missing' Error in Windows 10

I downloaded the MediaCreationTool on to a USB as suggested, plugged it in and followed the steps to the CMD Prompt.Here is what I get:

X:\sources>bootrec/fixmbr ---> The operation completed successfully.

X:\sources>bootrec/fixboot ---> Access is denied....

X:\sources>bootrec/rebuildbcd

Scanning all disks for Windows installations.

Please wait, since this may take a while...

Successfully scanned Windows installations.

Total identified Windows installations: 1

[1] C:\Windows

Add installation to boot list? Yes(Y)/No(N)/All(A):a

The system cannot find the path specified.

I'm unsure of what to do next, please advise.

[Moved from: Windows / Windows 10 / Windows update, recovery, & backup]

 

Installing windows off of a USB stick

Step By Step from vista:
From admin cmd prompt

1. diskpart
1a. list disk
2. select disk 1 (replace 1 with your usb drive)
3. clean
4. create partition primary
5. select partition 1 (replace 1 with your usb drive)
6. active
7. format fs=fat32
8. assign
9. exit

Copy Windows Vista's DVD ROM content to the Flash Drive

xcopy d:\*.* /s/e/f e:\ (d being your vista cd and e being your usb stick)

And that's it, boot off your usb disk

 

Dual Booting 2 x Windows 10 OS Drives (Existing Installs)


It is uneccessary to do all of the above.

1. Boot up Windows 10
2. Open Disk Management and take a note of the drive letter of the other Windows 10
3. Open Admin Command Prompt and type: bcdboot X:\Windows where X is the drive letter noted in step 2
4. Reboot, you should have a dual boot menu.