C#

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Threading;

public class WindowsForm : System.Windows.Forms.Form
{
	public static void Main()
	{
		Application.Run(new WindowsForm());
	}

	public WindowsForm()
	{
		Thread t = new Thread(new ThreadStart(GetData));
		t.Start();
	}
	
	private void GetData()
	{
		string query = "SELECT * FROM users";
		string constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\test.mdb;";
		OleDbConnection conn = new OleDbConnection(constr);
		OleDbCommand cmd = new OleDbCommand(query, conn);
		conn.Open();
		try
		{
			OleDbDataReader reader = cmd.ExecuteReader();
			while (reader.Read())
			{
				MessageBox.Show(reader.GetString(0));
			}
			reader.Close();
			conn.Close();	
		
		}
		catch(Exception e)
		{
				MessageBox.Show(e.Message);
		}
	}
}

[DllImport("advapi32.dll", SetLastError=true)]
static extern uint LsaEnumerateAccountRights(
       IntPtr PolicyHandle,
       IntPtr AccountSid,
       out string[] UserRights,
       out ulong CountOfRights);

AppDomain domain = Thread.GetDomain();
domain.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);
IPrincipal p = Thread.CurrentPrincipal;
if(p.IsInRole("YourServiceRole"))
{
    // do something here.
}