document.pif definition, relationships, removal:

This is a part of a malicious parasite that violates user privacy and damages the compromised system. The document.pif file can be used for different purposes depending on the related parasite's type, functionality and carried payload. Although document.pif may not take any malicious actions by itself, it ensures that a parasite is working properly and therefore needs to be removed. DO NOT open, execute or edit document.pif!
The document.pif file is installed and used by worm W32.Sobig.E.
In some cases a presence of document.pif does not mean that your system is infected. The file may actually belong to some fully legitimate applications and therefore must stay intact. If you are in doubt, please scan the document.pif file using you regular spyware remover or antivirus program.