How to install font in window via C#

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C#

VB

C#4.0

Hi all!
I want to create a program auto install font for window
I have copy file to %windir%\fonts, so it's accept denie ...
Can not install any font, also file(font)is exist ...
This my code

[DllImport("gdi32.dll", EntryPoint = "AddFontResourceW", SetLastError = true)]
        public static extern int AddFontResource([In][MarshalAs(UnmanagedType.LPWStr)]
                                         string lpFileName);
        int SumFileInstalled = 0;
try
            {
                string[] filePaths = Directory.GetFiles(textBox1.Text);
                string pathWin = Path.Combine(System.Environment.GetEnvironmentVariable("windir"),"Fonts");
                foreach (string temp in filePaths)
                {
                    try
                    {
                        string fileName = System.IO.Path.GetFileName(temp);
                        string destFile = System.IO.Path.Combine(pathWin, fileName);
                        System.IO.File.Copy(temp, destFile,true);
                        int result = -1;
                        int error = 0;
                        result = AddFontResource(destFile );
                        error = Marshal.GetLastWin32Error();
                        if (result == 0)
                            SumFileInstalled++;
                     }
                    catch (Exception ex)
                    {
                        int result = -1;
                        int error = 0;
                        result = AddFontResource(temp);
                        error = Marshal.GetLastWin32Error();
                        if (result == 0)
                            SumFileInstalled++;
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error system, please choose folder default - "+ ex.Message, "Error", MessageBoxButtons.OK);
            }
            MessageBox.Show(SumFileInstalled.ToString()+" : installed successfully.","The finish fonts.",MessageBoxButtons.OK);

plz help me!
i used VS2010, win7 Pro 32bit
Thanks all