A New Anti-Virus?

You may know about the programs and hardware devices created by Google to examine large amounts of code. Supposedly Able to read all the code contained within the Internet within a day. what if these types of programs were used on a personal level. Imagine examining all the code on your computer within a very short period of time. Being able to correct errors, and pin point viruses and other bad code instantly. It seems like a much better way of scanning your computer, then waiting for an hour while a anti-virus scans your computer and most likely misses a thing or two. Also a lot of computers now days defrag and clean up disk space on an automated basis. So in a sense to go further with my idea. What if we created a sort of "computer immune system" A sort of constant check for anything out of order and ability to correct it periodically. what do you think of this idea? I'm sure there are much finer details and problems but I am sure this would work.