I was at a friend's Christmas party, and just for kicks, I wrote a batch file that would display a message indicating his general inferiority. I placed it in the RUN key of his registry, with a name of "REALLYIMPORTANT", and went home. A month later, he contacts me and wants to remove it. Being a good guy, I walked him through the process of opening the registry, and, since i didn't want to direct him through the layers of keys, I told him to do a search for "c:\winnt\joke.bat". When it found the key, I told him to delete it, only to have him incredulously reply that he couldn't delete it, as it was "Really Important".