If you have high enough scinece you get give the scribe an idea that lets him contain the virus in one computer so then you only have two to worry about. When the scribe says "now" save the game. This way the computer with the virus will never change. So the its only a matter of finding those two computers.
I think the saving trick works even if you still have to find all three. If the screen does not have a bunch of gibberish just move on to the next.
Actually, you move on if the screen
does have a bunch of gibberish, the ones with the virus in them have a taunt on the screen. Unless you're referring to a portion of the virus you've already found, in which case disregard the previous comment.
Another trick you can use, but that I am not sure is actually WAI, also involves the partitioning. When you find the virus, click the 'partition' option three times in a row and it will isolate all three parts at once. Kind of a lazy way out, but it does work.