How to check shortcut file is exists on User desktop by C#?

I want to check shortcut of any installed software on user desktop is exists or not by C# programmatically. If exists then I want to change the rename of that shortcut. How to do this?

 

I tried this code to find shortcut but it's not well working. Shortcut file is exists but it displays "Shortcut File not found"

string desktopPath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
string shortcutfile = desktopPath + "\\Mozilla Firefox.lnk";
if (File.Exists(shortcutfile))
{
MessageBox.Show("Shortcut File found");
}
else
{
MessageBox.Show("Shortcut File not found");
}