Microsoft.Win32.RegistryKey regKey = Microsoft.Win32.RegistryKey.OpenRemoteBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, "ROB33N-PC/*(BILGISAYARIN ADI)*/");
regKey = regKey.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion", false);
if (regKey != null)
{
	DateTime date = new DateTime(1970, 1, 1, 0, 0, 0);
	Int64 regVal = Convert.ToInt64(regKey.GetValue("InstallDate").ToString());

	DateTime InsDate = date.AddSeconds(regVal);
}