[Help] Cannot run window mode.

Im using these files: darks team muserver-97d-99i-beta-42I've tried with different exe but still face same problem...

whenever I start exe it is like a fullscreen but with defined resolution... and therefore window is borderless without any controls.

Registry is setted to window mode 800x600

RegistryKey key = Registry.CurrentUser; // OUR REGISTERY
KEY key = key.OpenSubKey(@"Software\Webzen\Mu\Config", true);
key.SetValue("Resolution", 0x00000001,RegistryValueKind.DWord);
key.SetValue("ResolutionA", 0x00000001, RegistryValueKind.DWord);
key.SetValue("WindowMode", 0x00000001, RegistryValueKind.DWord);
key.SetValue("VolumeLevel", 0x00000005, RegistryValueKind.DWord);
key.Close();

Thats how exe is started
var startInfo = new ProcessStartInfo(this.MainExePath, "connect /u{IP WAS HERE} /p{PORT WAS HERE}")
;Process.Start(startInfo);

When is starts I got grey fullscreen and game in defined resolution within a square inside.
I've tried with other exe. But and for example HPTeam 0.97d+99i exe with minimizer turned on - creates same window but without grey background... and still game is borderless.

How can I fix it? To get minimizwd window with common borders?