You can have formatting and other issues when using powerpoint to run a presentation created in LO (although LO has come a long way in recent months), particularly if you use animations or complex slide transitions, or when Powerpoint has to substitute for fonts it doesn’t have installed. For best results, use the most recent version of LO, keep the presentation simple, use fonts that you know will be installed on the computer you will use for the presentation, make sure any images are saved in the presentation and not just linked to, and save it as a .ppt file. I would still always want to test it in MS Powerpoint first, and fix any minor formatting issues. If you are running Windows, you should be able to download and install for free a powerpoint viewer (if it is still available) that would enable you to check your presentation. Another approach is to use portable LibreOffice (www.portableapps.com) on a USB stick to run the presentation, and thus avoid any issues with MS Powerpoint altogether. This, of course, is subject to your school’s policy on such things