Enter Administrator Password or Power on Password

[Jenefaner]

I bought this laptop third hand from a neighbor. 

No passwords known. Error message after three failed attempts reads:

System disabled [i  86153857]

Please help and thank you in advance! 

[Paul_Tikkanen]

Hi:

Restart the PC, and enter this unlock passcode...11742618

[Jenefaner]

That code did something!! Thank you!!

Buuut.....now I have this:

gnu grub version 2.02 beta2-36 ubuntu3

I am so in over my head..... 

[Paul_Tikkanen]

You're very welcome.

Looks like someone removed windows and installed Ubuntu.

See if you can reinstall Windows 10 as follows...

To reinstall W10...Use the Media Creation Tool.  Make the 64 bit installation media.

https://www.microsoft.com/en-us/software-download/windows10

You can make a W10 USB flash drive installer using an 8 GB flash drive using another Windows PC, since your PC is not working.

W10 will find the product key in your notebook's BIOS, install and automatically activate once you are connected to the internet.

Here are the steps to create the W10 USB flash drive installer...

1. Select Download tool now, and select Run.
2. If you agree to the license terms, select Accept.
3. On the What do you want to do? page, select Create installation media for another PC, and then select Next.

4. Select the language, edition, and architecture (64-bit or 32-bit) for Windows 10. You want 64 bit.

5. Select which media you want to use:
6. USB flash drive.  Plug in a blank USB flash drive with at least 8GB of space. Any content on the flash drive will be deleted.

Then you can install the drivers and available software from your notebook's support page.

https://support.hp.com/us-en/drivers/selfservice/hp-pavilion-15-au000-notebook-pc-series-touch/10862...