This happened to me once:
I saved my powerpoint presentation in my flash drive for our report and when I opened it in our school computer, the font sizes was bigger than it originally was; thus parts of text can't be seen on the screen and our slides appeared messy and unorganized.
How do I avoid this from happening again? I wouldn't want to fix text sizes on the spot and right before our report because there might not be enough time to do so.
How can I keep my file from changing its format once it's uploaded on another computer?
The problem is not with your file. You will need to change the resolution of the monitor/projector of the machine used for your presentation.
How can I keep my file from changing its format once it's uploaded on another computer?
The file didn't change, the computer it was used in did. The fonts displayed depend on the fonts installed in the computer in which the file is displayed, not on the fonts in the computer in which it was created. The version of Powerpoint will also have an effect. The files is displayed by the Powerpoint program - if the school is using a different version, you may see differences from what the file looked like in your computer.
This is just the way Powerpoint presentations work - there's not much you can do to change it, except to use only fonts that you know are installed on the computer you're going to make the presentation in.
