Shruggle, a proof-of-concept virus discovered by Symantec Corp., is the first to target AMD's 64-bit processors. It infects only one system at a time by appending itself to 64-bit executable files, rather than spreading from machine to machine. Written in AMD64 assembly code (one can only imagine how geeky its author is...) the virus therefore only runs on AMD64 and not on 32-bit platforms. Regular 32-bit Windows users, therefore, have nothing to worry about from this particular virus, but with 64-bit Windows operating systems due to become the norm one day, this is worrying stuff.