What are these viruses about?

Recently I ran a virus scan on my removable drive and my NIS 2013 running on Windows 8.1 64 bits detected these two viruses and resolved the threats fro me.
Thanks to NIS 213, my removable drive is now free from viruses.

However, NIS calssified the threat level of these two viruses as high. So I'm to find out what are these two viruses, how it infect my and other people PC and what kind of damages can they do? 

 

Finally, is that any useful tips for me to prevent any futue infection to my removable drive? his is because I'm a universuty student so it's unavoidable for me to use my removable drive on a public PC and share it with m friends,

 

Thanks.