Estimate the install date of this system.

def Run(self, unused_args):
    """Estimate the install date of this system."""
    # Don't use winreg.KEY_WOW64_64KEY since it breaks on Windows 2000
    subkey = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE,
                            "Software\\Microsoft\\Windows NT\\CurrentVersion",
                            0, winreg.KEY_READ)
    install_date = winreg.QueryValueEx(subkey, "InstallDate")
    self.SendReply(rdfvalue.RDFDatetime.FromSecondsSinceEpoch(install_date[0]))