QUOTE (pgovotsos)
I know this might sound stupid, but what do you mean when you say "active points of infection"? What makes something no longer have active points of infection (Windows patches, no longer in the wild, etc)?
Usually that means no longer in the wild.
Windows patches are irrelevant. So many people refuse to update to the latest Service Pack, and many even turn off automatic updates. For example, the 'Conficker' worm that has been decimating computer relies on a security vulnerability in Windows that was patched a month before the worm was first seen. If people bothered updating their computers, it never would have happened.