Recover from Ubuntu 18.04 OEM account Latitude 5411MLK XCTO

Dear Dell Community,

What is the procedure to recover from Ubuntu 18.04 dell OEM account on Latitude 5411 MLK XCTO?

The settings icon has "..before shipping" but prompts for a password. Unfortunately, I don't have a passwords for this account.

How did I reach this stage:

I accidentally un-installed NVIDIA drivers, so to recover the original ubuntu drivers and settings, thought to recover Ubuntu from dell factory OS recovery mode by esc at the reboot. 

However even with multiple attempts the lshw -C display command kept saying NVIDIA "unclaimed". 

Tried to install the drivers over software center but failed and thus tried recovery to factory. In between fresh Ubuntu install also failed (got stuck , once made only root account). 

Again did factory OS reset and landed on OEM account.

Please help.

Thanks and regards

mm