My antivirus software found a virus in my local backup of my website. So I surfed to the corresponding URL on my site, and I'm looking at a black page that shows all directories and files on the hosting space. At the top is some ASCII graphics that say "GNY.Shell" . So I assume I've been hacked. Nobody's defaced the main page, but basically I need to know how to remove these files and prevent this type of thing from happening again.

Can anyone give me some pointers or a link to a tutorial about securing my site? It's running on ZenCart.

Thank you for any help! I'm going to go search on the zen cart site for some security tutorial posts.