Hi I am trying to install OS X but I got the message OS X could not be installed on your computer. No packages were eligible for install?

Delete the old OSX/macOS installer app in your Applications folder and download a current version from the web site in this link:

How to get old versions of macOS - Apple Support

- You may find you need to use Safari to get links for High Sierra and later using the Mac App Store application to open a functioning page.

- Sierra, El Capitan, and Yosemite download as a .pkg. Click on this to have a converted version placed in your Applications folder as an "Install OS..." application. Run the installer and follow the directions.