That way you get the maker's answer on this.
After avast found a problem on my computer, it removed it and after restarting it initiated a boot up scan. Now, every time I turn on the computer it does this. I have to hit esc to get it to stop. I wrote Avast who gave me this really complicated way of removing the software entirely. I even looked on these forums and never did see an actual solution to the problem. This has to be an easier way to do this. I have windows 7.