This is just a reply to all of you in this thread who helped me out (everyone’s answer was helpful), to let you know what happened.
I’m not a presentation expert by any means, and I had to deliver the presentation in less than 7 days (5 days after posting here), on a topic that I didn’t already know very much about. So I wasn’t going to be spending time learning how to incorporate animations or 3D effects because I had to spend most of my time just researching the topic itself.
For the visuals, I just needed a basic slideshow with pictures and text to carry me through.
After a few false-starts, and 3 hours wasted with OpenOffice (it wouldn’t allow me to open the presentation area - don’t ask me why), I downloaded LibreOffice Impress, and it worked.
It was very easy to use. I had to do the presentation in two languages, and Libre didn’t have a problem with that, well not much of a problem anyway - a few glitches in re-sizing non-English text.
I finished the final version on Tuesday (two days before the presentation) and I saved it in a few different formats onto a USB that I could take with me to the presentation. I also saved it onto the hard drive of my netbook in native LibreOffice format (of course). I didn’t know what resources they had at their firm but I wanted to be prepared for anything, or at least as much as I could, so I took both the USB and netbook with me.
When I arrived at their conference room I saw it was fully equipped for any kind of multimedia presentation. So rather than asking them to dick around with my USB saved files, I just plugged my netbook into their wall display and opened the document that I’d already played back to myself a hundred times.
It went without a hitch.
One thing about Libre though - I had planned to make handouts for everyone (something I hadn’t bothered to do ever before in other presentations), and I had assumed that it would be easy to derive handouts from an already created presentation, but I just couldn’t find out how to do it. The software was not very helpful in that regard:
‘Help’; ‘how to make handouts?’: ‘Yes!, you can make handouts in Libre!’, was about it.
My fault, I know, in that I didn’t know enough about how to use the software. But in a way it’s a good thing I didn’t give them handouts - no paper trail that I was ever there at their firm, and if they forget some important point that they need to know, they have to come back and ask me personally. To which I can suggest that if they hire me, I can remind them. 
So thanks again all!