I also still have LibreOffice 3 installed on this machine. I didn’t see any uninstall, uinstall or similarly-named program in the LibreOffice directory, but all is not lost.
If you still have the installation file(s), e.g., LibO_3.6.5_Win_x86_install_multi.msi (main program) and LibO_3.6.5_Win_x86_helppack_en-US.msi (help pack), you can run them, starting with the help pack, and on detecting that it is already installed, will give you the option to repair or remove the product.
On installation, you would generally:
- run the install of the main program, then
- run the install of the help pack.
So on removal, you normally should do it in the reverse order:
- run the uninstall of the help pack, then
- run the uninstall of the main program.
If you don’t have them, you should be able to download them by going to the download page at http://www.libreoffice.org/download/, click on “Change System, Version or Language” and navigate to your platform, language, and then pick the appropriate LibreOffice 3.6 version. (It doesn’t matter that much that what you had installed was probably an earlier 3 version, the latest 3 version installer should work for purposes of uninstalling.
If that doesn’t work, a trick I find that sometimes work with various applications is to install the version I want to remove, and that will put in all of the pieces to get the regular uninstall routines to work correctly. So if you aren’t given an option to uninstall, this would take more time, but I think I would suggest going through the installation process (main program, then the help pack), and then using either the Windows “Control panel” → “Programs” → 'uninstall a program" or using the installation files to go through the uninstall process (help pack, then the main program).