It's relatively original, except...
It's relatively original, except for the stick figure fighting bit - which is pretty standard stuff. Some suggestions:
A preloader. It sucks not knowing when to press play - on my browser, it's not always clear when a flash movie has loaded.
When the virus warning pops up, I think it would be better if the dialog box had a "disinfect?" button, and the stick guy looked up, and tried frantically to jump high enough to press the button, but failed.
Once the "ninja death virus" arrived, it would be better if it looked more ninja-like... With a vague suggestion of a ninja outfit, and maybe it could throw some ninja stars, or drop down on a rope, or something. Some unneccesary jumps and flips would be cool too, and I think add some humor.
Some easter eggs would be cool - Like if you clicked on an icon, a window might open up, and he'd have to interact with that window... Of course, that might get very complex, but it would ROCK if done right.
I'd definitely like to see you continue working on this - yes, the stick fighting thing has been done to death, but this is an original concept. Don't fall into the trap of just having it be fight after fight in different areas of windows... Have the guy interact with windows in different ways, and add more humor, I think that's the way to go with this. So far so good - Keep it up!