I had extra hard disk on my PC. The primary hard disk failed. I was installing Ubuntu and by mistake I allowed to format the disk by Ubuntu installation programme.
How do I recover the videos, pictures and text documents using Qtest disc or Recuva?
Hello, if your failed disk was recognized by the ubuntu installation that would mean that the drive is/was not completely dead. You could try starting your system from the ubuntu live disk option and explore the failed drive. Make sure that you failed disk is mounted and then navigate to the folders where the files you want to recover are located. If the installation did not complete, you might be able to recover the files.
Ubuntu Documentation - Data Recovery
How to Recover Deleted Files in Ubuntu / Debian with Scapel and Foremost
A lot of files will be permanently lost, depending on how far into the installation Ubuntu got.