MSupdate.exe definition, relationships, removal:

MSupdate.exe is an executable file which primary purpose is to start a parasite or launch some of its components. Once executed, the MSupdate.exe file runs a process that is responsible for the parasite's payload. MSupdate.exe is a significant part of a dangerous threat, but it can also work on its own. DO NOT execute it!
The MSupdate.exe file is installed and used by browser hijacker CoolWebSearch.msupdate. It is also related to other parasites such as Affilred and PSN. These threats can use MSupdate.exe for different purposes, as the file's functionality depends on a particular parasite it belongs to.
In some cases a presence of MSupdate.exe 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 MSupdate.exe file using you regular spyware remover or antivirus program.