I have dealt with a similar situation before ... I never got the actual
identity of the user but using

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/termserv/TermSe
rv/wtsgetactiveconsolesessionid.asp
an
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/termserv/TermSe
rv/wtsquerysessioninformation.asp

I was able to get the name of the user (including fast switching for
multiple users).

Cheers,

Greg

You could use the ServiceControl control to start service when your app
starts. Or put your app in the Startup folder.

private void button18_Click(object sender, EventArgs e)

{

   WindowsIdentity wi = WindowsIdentity.GetCurrent();

   Console.WriteLine("Current User: " + wi.Name);

   foreach (IdentityReference ir in wi.Groups)

   {

       NTAccount acc = (NTAccount)ir.Translate(typeof(NTAccount));

       Console.WriteLine("Member of: " + acc.Value);

   }

}