New
#31
If I understand you correctly.
You have .pps files that you know have sound because you created and saved them with sound, with the trial MS Office or even with any MS Office product.
But, when you use Libre Office Impress/Presentation to open them, they don't have sound.
They may just need converting:
Try saving one of your .pps files as .ppt or even .pptx depending on the version of the MS trial you used.
I would use the Save As command, that way you won't disturb the original file.
Open the file and see if it then plays correctly.