Update all the people with ie6 to something newer
How difficult would it be to write a virus that fixed common system vulnerabilities? Could one write something that would run Windows Update, download Spybot and some other free antivirus programs to do a sweep, update Java and Flash, etc.?
I imagine it's similar to the biochemical changes that occur in a newly fertilized egg to prevent entry of additional sperm.
I could be wrong though. As I say I haven't exactly researched this.