How exactly does it get on your comp?
When you plug the infected USB in.
But how is it getting on the (I'm assuming you mean flash drive type USB storage) in the first place? Or is it something that's affecting printers (through drivers) and other USB devices?
Printers aren't a good choice for spreading a virus for the simple reason that you aren't likely to move it from one computer to another. USB mice and keyboards don't store data as far as I know. Flash drives on the other hand are intended for data storage and use on multiple computers. I imagine that when the virus is running a process that detects when a flash drive is put into a machine and then it copies itself onto it.
