XPS One 2710 Error Code: 0xc000000f

"Old faithful" has let me down! Bought in 2013 as a Win7 device, upgraded to Win10 in 2015 and it has never missed a beat ... until now. Recent power failure while running resulted in endless repair loop on bootup. Ran diagnostics from BIOS, no faults detected. Successfully booted from USB and brought back to life from a restore point.

Then an abnormal shutdown during the latest Win10 update. Endless repair loop on bootup again. Restored again using USB boot but this time had to go back to an older restore point to bring back to life. Ok, this is getting scary. Turned off Windows Update. Ordered a new Inspiron 27 7700.

Accidentally interrupted power while moving Old Faithful to set up the new PC. Another abnormal shutdown ... you get the picture. This time it won't restore from Backups or System Image (I keep them all on an external backup drive), but it does give me the opportunity to reinstall Windows from the cloud so I do that. Success!!! Get bold and run all updates. Success!!!!   Young family don't have a PC so I figure on setting this up for them. Update BIOS to A14. Sweet. Run Dell Diagnostics and PC freezes, won't respond to CTRL ALT DEL. Use power button to turn off PC, now get Error Code: 0xc000000f 'your device needs to be repaired'. Over and over the same. Rats! chkdsk says no errors found but cannot run /f or /r switches because volume cannot be (locked/unlocked .. can't remember which now).

I'm figure the problems are in the boot sector, would appreciate thoughts on whether I should just flick an new HDD into it. Thanks in advance.