i have a code to get the groups a user belongs to.

try 
        {
            DirectoryEntry adRoot = new DirectoryEntry(string.Format("WinNT://{0}", Environment.UserDomainName));

            DirectoryEntry user = adRoot.Children.Find(completeUserName, "User");                
            object obGroups = user.Invoke("Groups");
            foreach (object ob in (IEnumerable)obGroups)
            {
                // Create object for each group.
                DirectoryEntry obGpEntry = new DirectoryEntry(ob);
                listOfMyWindowsGroups.Add(obGpEntry.Name);
            }
        return true;
        }
        catch (Exception ex)
        {
            new GUIUtility().LogMessageToFile("Error in getting User MachineGroups = " + ex);
            return false;
        }

the above code works fine when i have to find the groups of a local user but

for a domain user it returns a value "Domain User" which is kind of wierd as it is a part of 2 local groups.

Please can some1 help in solving this mystery. thanks

Research

I did some finding and got that i am being returned the primary group of the domain user

called "Domain User" group

but what i actually want is the groups of the local machines the domain user is a part of... i cannot get that.. any suggestions

another code using LDAP

        string domain = Environment.UserDomainName;
        DirectoryEntry DE = new DirectoryEntry("LDAP://" + domain, null, null, AuthenticationTypes.Secure);
        DirectorySearcher search = new DirectorySearcher();

        search.SearchRoot = DE;         
        search.Filter = "(SAMAccountName=" + completeUserName + ")";  //Searches active directory for the login name

        search.PropertiesToLoad.Add("displayName");  // Once found, get a list of Groups

        try
        {
            SearchResult result = search.FindOne(); // Grab the records and assign them to result
            if (result != null)
            {
                DirectoryEntry theUser = result.GetDirectoryEntry();
                theUser.RefreshCache(new string[] { "tokenGroups" });
                foreach (byte[] resultBytes in theUser.Properties["tokenGroups"])
                {
                    System.Security.Principal.SecurityIdentifier mySID = new System.Security.Principal.SecurityIdentifier(resultBytes, 0);

                    DirectorySearcher sidSearcher = new DirectorySearcher();

                    sidSearcher.SearchRoot = DE;
                    sidSearcher.Filter = "(objectSid=" + mySID.Value + ")";
                    sidSearcher.PropertiesToLoad.Add("distinguishedName");

                    SearchResult sidResult = sidSearcher.FindOne();

                    if (sidResult != null)
                    {
                        listOfMyWindowsGroups.Add((string)sidResult.Properties["distinguishedName"][0]);
                    }
                }
            }
            else
            {
                new GUIUtility().LogMessageToFile("no user found");

            }
            return true;
        }

        catch (Exception ex)
        {

            new GUIUtility().LogMessageToFile("Error obtaining group names: " + ex.Message + " Please contact your administrator."); // If an error occurs report it to the user.
            return false;
        }

this works too but i get the same result "Domain Users" . Please can some1 tell me how to get the local machine groups...????