Windows Service not opening application GUI

Question

I'm trying to open an application(with it's GUI) thorough the windows service. It's not throwing any exception or error. Its not opening the application. When I executed the same code with windows Forms app the applicaiton is opening. Why the windows service is not opening any other application? My code is like below:

        protected override void OnStart(string[] args)
        {
            try
            {
                bool isinstalled = checkInstalled("AnyDesk");
                if (isinstalled)
                {
                    Process.Start(@"C:\Program Files (x86)\AnyDesk\AnyDesk.exe");
                }
            }
            catch (Exception ex)
            {
                this.EventLog.WriteEntry(ex.Message, EventLogEntryType.Information);
            }
        }



        public static bool checkInstalled(string c_name)
        {
            string displayName;

            string registryKey = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
            RegistryKey key = Registry.LocalMachine.OpenSubKey(registryKey);
            if (key != null)
            {
                foreach (RegistryKey subkey in key.GetSubKeyNames().Select(keyName => key.OpenSubKey(keyName)))
                {
                    displayName = subkey.GetValue("DisplayName") as string;
                    if (displayName != null && displayName.Contains(c_name))
                    {
                        return true;
                    }
                }
                key.Close();
            }

            registryKey = @"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall";
            key = Registry.LocalMachine.OpenSubKey(registryKey);
            if (key != null)
            {
                foreach (RegistryKey subkey in key.GetSubKeyNames().Select(keyName => key.OpenSubKey(keyName)))
                {
                    displayName = subkey.GetValue("DisplayName") as string;
                    if (displayName != null && displayName.Contains(c_name))
                    {
                        return true;
                    }
                }
                key.Close();
            }
            return false;
        }

Answer 1

Windows Service applications run in a different "window station" than the logged-on user. Your application is opening and displaying on a hidden desktop that nobody can see.

See: https://docs.microsoft.com/en-us/dotnet/framework/windows-services/introduction-to-windows-service-applications