如何删除OpenLayers-Map中的标准控件?

I use OpenLayers and want to create another navigation-control in the upper-left side. I know how to add Controls, but this navigation is added at default while creating the OpenLayers-Map. So I want to remove that Control, to add an own. I know already, that the default-control is an OpenLayers.Control.PanZoom.I use OpenLayers and want to create another nav