Virus in Camera
Your model doesn't come with built-in storage, so that makes this easier. You should first put in another SD card and see if that helps. If it does, you'll probably have to reformat your first SD card, wiping everything on it. Sometimes formatting issues appear to Windows like a virus on an external device. If this does not fix the virus warning problem, then your virus is likely on your computer, not the camera.
A good virus scanner/remover might be in order for your computer.
Hope this helps. Good luck