Q> Как сделать чтобы окошко не появлялось на таскбаре?
A>

There is more than one way to stop a window appearing on the taskbar.

Rather than WS_EX_APPWINDOW, give your window the WS_EX_TOOLWINDOW extended
style. Since toolbars don't appear on the taskbar, this will prevent it
appearing there. Unfortunately, this has some rather negative repercussions
on the appearance of your window : it gets a thin caption with smaller title,
and loses its system menu. This is not acceptable to many people.

Windows owned by an invisible window won't appear on the taskbar. "Great",
say you, "but my app is dialog based, so what now Mr Smarty ?". Well, you can
either recast your dialog app as an SDI with a hidden main window, and have
that main window shown at startup, or you can create your own hidden window
and set that as your dialogs owner.