On some of our PC's, the quick launch bar background is black and it cannot be made smaller. Also the two vertical bars on the rest of the toolbar have black backgrounds. If the quick launch bar is dragged onto the desktop, the window is black. Tried deleting shelliconcache and playing with desktop properties and colour schemes-no good. Also tried tweakui to do a rebuild on the icons-no good. Tried deleting quick launch folder and recreating it. This allows me to resize the quick launch bar, but the background is still black! Is there anything else to try?