USB Disk Security removes most trojans from flash disks when it is inserted.
Winrar can be downloaded free and one uses it to open any removable storage media. Folders appearing as applications are always viruses and you should delete them, any other item also appearing with a recycle bin icon is a virus. It shows all the hidden files and they cannot get into the PC without you trying to open the files or copying them.
For viruses you get on accessing the internet you must have an antivirus.
Birds of a feather flock together