Manual "Escape" from MSCONFIG settings (i.e., Diagnostic Boot)

Once again, I've proven my handle to be correct. Clearly the problem lies within the confines of the little plastic box and not the highly intelligent, devastatingly handsome tech sitting in front of it!

Customer brought me an Aspire E1-510P (Acer) last night. She presumably has done everything correctly that I've previously advised. Patiently waited for the Win10 upgrade to happen on its own, didn't even use the Media Creation shortcut. It appears as though she upgraded (as instructed) and has not performed a clean install (unlike so many of you...er...us!).

Presented with what I presumed to be either a video driver fault or some unknown auto-run incompatibility with something leftover from her 8.1 install. Sure, I can fix that.

Boots to the Windows 10 desktop but the display is stuck in what appears to be an endless loop of DISPLAY-->flash -->DISPLAY ... so bad is whatever is going on that I cannot bring up the start menu, a context menu from the desktop or virtually anything else.

I'm able to finally bring up a task manager and launched MSCONFIG from which I configured a diagnostic boot with only MS services enabled. Reboot.

In this diagnostic mode as you likely already are aware, the PIN sign-on reverts automatically to her Microsoft password. Which she has somehow completely forgotten in the last 11 or 12 hours. Finally, two drinks and several attempts later, we are at least able to RESET her Microsoft password via my PC and the MS Website. No problem.

EXCEPT that her PC is still under the effects of the diagnostic boot and is no longer picking up my Wi-Fi signal. Nor is it able to connect via Ethernet. (You see where I'm going with this, huh?) Yup...even though we have successfully reset the Microsoft password, sans internet, the PC has no idea of this fact nor any inkling of what the new password now IS.

Showing my age, I know, but are the parameters within the msconfig settings stored somewhere I can easily get to them with direct disk access? I cringe to say it, but back in the day such things were easily found (and corrected or erased) in config,sys and win.ini, etc.

Please help before I lose my temper and become that really old PC guy that has just fixed one system too many and subsequently reverts back to communication only by 300 baud modem and soft-scroll text on a 40x80 monochrome screen.

Help me Obi Wan Kenobi....you're my only hope!