uninstall.dat definition, relationships, removal:

uninstall.dat is associated with a dangerous computer parasite that attempts to violate your privacy by spying on you and stealing your confidential information or harm your system by running a devastating payload or spreading routine. The exact functionality of the uninstall.dat file depends on the related parasite's type and purpose. In any case, you should NOT open this file!
The uninstall.dat file is installed and used by keylogger Employee Watcher. It is also related to other parasites such as keylogger ICE Remote Spy, keylogger Is My Mate Cheating Online, keylogger Key Logger Buddy Pro, keylogger KidWatcher, keylogger Spy Software 4 Parents and keylogger Probot. These threats can use uninstall.dat for different purposes, as the file's functionality depends on a particular parasite it belongs to.
In some cases a presence of uninstall.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 uninstall.dat file using you regular spyware remover or antivirus program.