Finally successfully installed Lubuntu 18.04 LTS into my old 2008 Macbook white to extend its life. There was an inclusion of AbiWord and Gnumeric in the OS installer, but I need a presentation program that's compatible with my old Powerpoint files. I used the Synaptic Package Manager to download the LibreOffice suite but found the Impress program to be unstable in my machine. Causes crashes when I make new presentations, when I try to save files, or when I start a slideshow. What's out there that's for Ubuntu, and are free, stable, Powerpoint pptx compatible, and easy to install? TIA