Splash Screen waiting until thread finishes

I still have a problem with the splash screen. I don't want to use the property SC.TopMost=true.

Now my application scenario is as follows:

in progeram.cs:

[STAThread]
static void Main()
{
    new SplashScreen(_tempAL);// where _tempAL is an arrayList
    Application.Run(new Form1(_tempAL));
}

in SplashScreen class:

public SplashScreen(ArrayList _Data)
{
    DisplaySplash()
} 
private void DisplaySplash()
{
    this.Show();
    this.TopMost = true;
    this.CenterToScreen();
    this.SetTopLevel(true);

    _allServerNarrators = new string[10];
    for (int i = 0; i < _allServerNarrators.Length; i++)
        _allServerNarrators[i] = null;

    GetFromServer();

    this.Hide();
    _serverData = new ArrayList();
    _thisData.Add(_allServerNarrators);
    _thisData.Add(_serverNarrators);

}
private void GetFromServer()
{
    _serverNarrators = new ArrayList();
    string _file = "Suras.serverNar";

    if (!Directory.Exists("c:\\ASGAQuraan"))
        Directory.CreateDirectory("c:\\ASGAQuraan");

    while (counter < 4 && _serverFiles == null)
    {
        if (Download("c:\\ASGAQuraan", _ftpServerIP, _file))
        {
            StreamReader _strReader = new StreamReader
                         ("c:\\ASGAQuraan\\"+_file,System.Text.Encoding.Default);
            string _line = _strReader.ReadLine();
            string _word;

            while (true)
            {
                while (_line != null)
                {
                    _word = _line.Substring(0, _line.IndexOf("*"));
                    int _narId = Convert.ToInt32(_word);
                    _line = _line.Substring(2);
                    int k = 0;
                    _serverNarratorNode = new ArrayList();
                    while (true)
                    {
                        int ind = _line.IndexOf("*");
                        if (ind > 0 && ind