detect invalid shortcuts

// reference %systemroot%\system32\shell32.dll
// that will generate an interop wrapper
Shell32.ShellClass Shell = new Shell32.ShellClass();
Shell32.Folder folder = Shell.NameSpace(@"./SomePath");
Shell32.FolderItem file = folder.Items().Item("nameofshortcut.lnk");
Shell32.ShellLinkObject link = (Shell32.ShellLinkObject)file.GetLink;

string Link_Path = link.Path;
if(!File.Exists(LinkPath)
{
    //Do something appropriate here
}