private int width = Screen.PrimaryScreen.Bounds.Width;
const int WM_NCLBUTTONDOWN = 0x00A1;
const int WM_NCHITTEST = 0x0084;
const int HTCAPTION = 2;
[DllImport("User32.dll")]
static extern int SendMessage(IntPtr hWnd,
int Msg, IntPtr wParam, IntPtr lParam);

protected override void WndProc(ref Message m)
{
    if (m.Msg == WM_NCLBUTTONDOWN)
    {
        int result = SendMessage(m.HWnd, WM_NCHITTEST, IntPtr.Zero, m.LParam);
        if (result == HTCAPTION)
            return;
    }
    base.WndProc(ref m);
}

private void Form1_Load(object sender, EventArgs e)
{
    //привязка формы к определенному месту экрана

    //верх правого угла экрана
    this.Location = new System.Drawing.Point(width - this.Size.Width, 0);
}

using System.IO;

public static bool IsLocal()
{
    DirectoryInfo dir = new DirectoryInfo(Application.StartupPath);
    return (from d in DriveInfo.GetDrives()
            where string.Compare(dir.Root.FullName, d.Name, StringComparison.OrdinalIgnoreCase) == 0
            select (d.DriveType != DriveType.Network)
            ).FirstOrDefault();
}

private void button1_Click(object sender, EventArgs e)
{
    if (IsLocal() == true)
    {
        MessageBox.Show("Запущен на локальной машине");
    }
    else
    {
        MessageBox.Show("Запущен из сети");
    }
}

using System.Runtime.InteropServices;

[DllImport("user32.dll", SetLastError = false)]
static extern IntPtr GetDesktopWindow();

[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr GetWindow(IntPtr hWnd, GetWindow_Cmd uCmd);

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool EnableWindow(IntPtr hWnd, bool bEnable);

enum GetWindow_Cmd : uint
{
    GW_HWNDFIRST = 0,
    GW_HWNDLAST = 1,
    GW_HWNDNEXT = 2,
    GW_HWNDPREV = 3,
    GW_OWNER = 4,
    GW_CHILD = 5,
    GW_ENABLEDPOPUP = 6
}

private void button1_Click(object sender, EventArgs e)
{
    //получаем первое дочернее окно Рабочего стола
    IntPtr hwnd = GetWindow(GetDesktopWindow(), GetWindow_Cmd.GW_CHILD);
    if (hwnd != IntPtr.Zero)
    {
        //перебираем все окна в системе
        while (hwnd != IntPtr.Zero)
        {
            //проверка, что блокируем не свое окно
            if (hwnd != this.Handle)
            {
                //блокируем окно 
                //(вид окна, как будто его блокирует диалоговое окно)           
                EnableWindow(hwnd, false);
            }
            //получаем хендл следующего окна          
            hwnd = GetWindow(hwnd, GetWindow_Cmd.GW_HWNDNEXT);
        }
    }
}

IntPtr nextClipboardViewer;

public Form1()
{
    InitializeComponent();
    nextClipboardViewer = (IntPtr)SetClipboardViewer((int)
                this.Handle);
}
[DllImport("User32.dll")]
  protected static extern int
            SetClipboardViewer(int hWndNewViewer);
[DllImport("User32.dll", CharSet=CharSet.Auto)]
public static extern bool
         ChangeClipboardChain(IntPtr hWndRemove,
                              IntPtr hWndNewNext);
[DllImport("user32.dll", CharSet=CharSet.Auto)]
public static extern int SendMessage(IntPtr hwnd, 
                                     int wMsg,
                                     IntPtr wParam,
                                     IntPtr lParam);

protected override void WndProc(ref System.Windows.Forms.Message m)
{              
    const int WM_DRAWCLIPBOARD = 0x308;
    const int WM_CHANGECBCHAIN = 0x030D;

    switch (m.Msg)
    {
        case WM_DRAWCLIPBOARD:
            DisplayClipboardData();
            SendMessage(nextClipboardViewer, m.Msg, m.WParam,
                        m.LParam);
            break;

        case WM_CHANGECBCHAIN:
            if (m.WParam == nextClipboardViewer)
                nextClipboardViewer = m.LParam;
            else
                SendMessage(nextClipboardViewer, m.Msg, m.WParam,
                            m.LParam);
            break;

        default:
            base.WndProc(ref m);
            break;
    }
}

void DisplayClipboardData()
{
    try
    {
        IDataObject iData = new DataObject();
        iData = Clipboard.GetDataObject();

        if (iData.GetDataPresent(DataFormats.Rtf))
            richTextBox1.Rtf = (string)iData.GetData(DataFormats.Rtf);
        else if (iData.GetDataPresent(DataFormats.Text))
            richTextBox1.Text = (string)iData.GetData(DataFormats.Text);
        else
            richTextBox1.Text = "[Clipboard data is not RTF or ASCII Text]";
    }
    catch (Exception e)
    {
        MessageBox.Show(e.ToString());
    }
}

protected override void Dispose(bool disposing)
{    
    if (disposing)
    {
        if (components != null)
        {
            components.Dispose();
        }
    }
    base.Dispose(disposing);
}

protected override void Dispose(bool disposing)
{
    ChangeClipboardChain(this.Handle, nextClipboardViewer);
    if (disposing)
    {
        if (components != null)
        {
            components.Dispose();
        }
    }
    base.Dispose(disposing);
}