Unlicensed releases are a trial. When that ends, certain features are disabled. There is a free VP release with limited features. If it balks at mp4 exports, try the AVI format. As mentioned, you can always reinstall your old release. If you don't have the installer, get it or any version within your six-month purchase grace window here and it should be licensed. Ignore virus warnings.
Links to screenshots that you have uploaded to a (free) server can be posted to the forum. Clicking on the link takes users to the shot. On the server click Share or Get Link and be sure it's not "restricted." That's the Google Drive default. Change it to "Anyone with Link Can View." This is essentially the same as the procedure you used to share the project file.
You don't need WinZip. 7zip is free. But it's likely that neither is needed: the right-click on a zip file, then Extract All works fine in Windows.