I have a Matrox Millenium graphics card and the windows blink and flash when moved.

A. If you are using the graphics card at 1600 x 1200 resolution in True Color (24-bit) or True Color (32-bit) mode, a window's frame may blink or flash when you drag the window across the screen. This is a known problem, and resolve, enable the Show Window Contents While Dragging option from the Plus tab on the Display control dialog (Start - Settings - Control Panel - Display)