My machine do not crash, Norton did not detect any virus ... nor did my 5 friends that are racing with me. One had lockups runing the game, that was corrected once he installed the latest video drivers. The downloader you are talking about is Steam, it's the application that launches on your PC to allow you to get/verify/connect online/check update to the game. You can set it up so it doesn't autoconect on start up.
Don't freack out like that:lol