Comment 4 for bug 1815529

For help with lost passwords see: https://help.ubuntu.com/community/LostPassword

But you will not be able to update the machine or install any new software as the repositories have been moved and were frozen in 2017. To use the machine on the internet will be a security risk.

It is *best* to download a supported Ubuntu release to get updates and security fixes.

You can find help with your problem in the support forum of your local Ubuntu community http://loco.ubuntu.com/ or asking at http://askubuntu.com or https://ubuntuforums.org.