If you want to find the minimized state for other windows,
[DllImport( "User32.dll" )]
static extern int FindWindow( String ClassName, String WindowName );
[DllImport("User32.dll")]
private static extern bool IsIconic(int hWnd);
usage -
//get the window handle
int hwnd = FindWindow(null,"Some window title");
bool bMinimized = IsIconic(hwnd);
if bMinimized == true //its minimized