I loaded the latest version of LibreOffice and it does not open. I wish to uninstall it and reinstall an older version. How do I do this?
More information please. Downloading a program isn’t enough to run it, you normally have to install it as well. Did you do that? Base requires Java, do you have that on your pc? Etc.
Your question has nothing to do with this site. Follow the standard procedure for your operating system.