My MP4 videos stored on my computer are freezing, as if the computer is unable to display the video. When I used Mint, the videos ran fine, so I suspect it might be a different video driver, but I'm not sure how to check since I'm a begginer.
The computer configuration is:
Intel Pentium N3540 processor, 4GB of Ram and 120GB SSD.
If that doesn't solve the problem, you might want to take a look at Zorin Lite, as the xfce desktop it uses is far less resource-hungry than the gnome desktop used in Zorin Core
Like suggested I would say that you try it in Xorg. Then You could take a Look at the Codecs. Open the Gnome Software Cente and scroll on the Start Page all the Way down to the End. There You should see other Categories and there ist the ''Codecs'' Category. What isn't installed You could install.
Then would be the Ubuntu Proprietary Package. That is a Package with AV-Codecs and Microsoft Fonts. To install that, open the Terminal and type sudo apt install ubuntu-restricted-extras
When it installs You will get a Screen to accept an Licence Agreement for the Microsoft Fonts. That is normal.
When I installed ubuntu-restricted-extras, my videos got an error messagem: "Internal data stream error."
I saw in another place that I should use VLC installed by command line (sudo apt install vlc) instead of by the store (I don't know why). I tried that and I had success running local MP4 videos on VLC.