The closest approximation we have for “a computer that runs all the programs except the one you don’t like” is “a computer that is infected with spyware out of the box.” By spyware I mean operating-system features that monitor the computer owner’s commands and cancel them if they’re on a blacklist. Think, for example, of image scanners that can detect if you’re trying to scan currency and refuse to further process the image. As much as we want to prevent counterfeiting, imposing codes and commands that you can’t overrule is a recipe for disaster.

Why? Because for such a system to work, remote parties must have more privileges on it than the owner. And such a security model must hide its operation from the computer’s normal processes. When you ask your computer to do something reasonable, you expect it to say, “Yes, master” (or possibly “Are you sure?”), not “I CAN’T LET YOU DO THAT, DAVE.”