Here's a root kit that is nearly impossible to detect:
Mebroot Root Kit
And once again, the infamous IT experts all over this country said this type of thing was hypothetically possible but beyond the reach of most malware writers.
Verisign says 5000 people were discovered to be infected since this was discovered in December.
And check out what you have to do to detect it.
This thing can be installed onto your machine in a drive by visit to a web site.