Even though Brian is a gigantic idiot, I think he would probably have at least an anti-virus.
Its called a Crypter. Which makes the virus UNDETECTABLE by EVERY anti-virus.
"a crypter is usally a program to hide detections. it's main work it to keep data encrypted, and decrypt it only when it needs to execute it.
In other words : "ABCD12" is a virus. if you download it every av will go insane.
Now let's say "C" is the crypter.
we save a file containing "C" & "21DCBA". you can see that's the crypter and the virus, reverted. now "21DCBA" won't be detected, as it has no sense. when "C" runs, it will Change the data next to it to it's original state through a specific algo (in this case it will reverse it back to the virus) and will run it."
Source: Interwebs.
