seeking reassurance about my computer, any help

how would i know that i had a virus on my desktop computer which was deleting my media files, like pictures and music?

sometimes i check media folders on my computer, and there looks like there's less media files in the folder than i thought? i thought there was more....could this be a virus? would malware or a virus delete your files gradually one by one over time or all in one go?

hopefully my files are safe and there's no virus, hackers or malware deleting my files.