Well sir it seems you know nothing about viruses. There is something called crypting, which makes your virus not even detectable by the best AntiVirus software. Sorry to burst your bubble. I'll add that in the topic before a bunch of morons jump on the thread.
well sir it seems you think you know everything there is to know. no matter how well you crypt, it is never perm, after a while the virus will flag, it just takes longer, using something like kaspersky and aiming it directly at what you suspect to have a virus will tear appart that crypt so fast, a crypt ususally takes a while to get broken though because the computer cant see it initially and slowly works it way through. if you went to specifically target the file it will show.
NO SHIT SHERLOCK, thats why you dont use public crypters, buy a private stub and your virus will be FUD or only detected by 1-2 AV's for a long time if you know what you're doing.