hgzip.dat definition, relationships, removal:

This is a part of a malicious parasite that violates user privacy and damages the compromised system. The hgzip.dat file can be used for different purposes depending on the related parasite's type, functionality and carried payload. Although hgzip.dat 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 hgzip.dat!
The hgzip.dat file is installed and used by HGZ.
In some cases a presence of hgzip.dat 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 hgzip.dat file using you regular spyware remover or antivirus program.