Just watched this movie from 2004, features Lance Henrikson in a role.
Theories of mine below…
Henrikson is a serial killer, he has been drugging the buildings water or through the wine he offers the main character. We see the landlord dead with his skull cut off, the exact same way the main character is killed. Henrikson had some dialogue where he said he needed to pull his hard drive or something. This would also explain the general weirdness like packages and blood tests and nano machines etc.
Or the nano machine plot is real, maybe related to the code the main character writes for a living?