You don’t want to lose your presentation slide deck due to a computer virus. You hear more stories about ransomware that could encrypt all your files. It would be a shame if you can’t access your precious presentation and supporting files anymore.
You will find plenty of tips online about how to reduce the risk of losing your files. Ensure up to date software, arrange for a backup of your files.
Keep the backup somewhere else safe and secure.
Bring the files that you need for a presentation also with you on a USB stick and don’t save the USB stick in your laptop bag, but keep it safe somewhere else (for example together with your keys on a string).