I have received a few Xmas cards using powerpoint. Is their an Ubuntu equivalent to open this file?
Ubuntu comes with LibreOffice, an office suite that replaces Microsoft Office. The LibreOffice equivalent to Microsoft PowerPoint is called Libreoffice Impress. In any case, you should be able to open you PPT or PPTX files by simply double-clicking the file.
To my experience, Libre Office has a lot of problems rendering properly ppt or pptx documents. The presentation is most of the time not matching at all the original document and the layout is often so messed up that it is almost impossible to read.
That has made me order at work a computer with Windows with the MS Office suite because I am unable to open documents (Excel, Word or PowerPoint) shared by colleagues to amend it.
And I have never been fully satisfied with MS Office suite over Wine as well.
That said, I do use Libre Office at home for most of my documents and it works very well if you stay in Libre Office.