i think that USB is already infected with a virus and putting it in another pc will probably infect that pc. so take precaution before doing that move.
ako cguro butahon kung maka encounter ko ana nga problem kay ako icheck first ang pc kung naay virus. maybe naay running nga exe (malware or a virus) nga nag binuang sa usb flash drive, or how to describe that.
daghan ways to check if your pc is infected and i can't detailed it here.
there are times nga dli maka detect ang Anti-virus bisag unsaon. i have tried it so many times. murag na immune ang AV.