My hard disk is acting up abnormally

Hello there, Tomorrow i transferred my data from mobile to pc it's doned easily without any hassle but when I open my computer today i saw only the folder is visible but the folder contents (files) are deleted, gone not all data deleted i mean half content are deleted i don't know why.
many says it maybe a virus or ransomeware but if it's virus or something then why it effects only half transfered contents why not the whole harddrive?

Please help me if someone face this kind of problem

Thank your 🙏