By flickering you mean to say when you exit sleep mode, or turn the computer on? This happens with a Vista machine I am using. Everytime I switch displays, it flickers like three to four times. What I assume, this is Vista attempting to aline itself with the attached display devices/device. I have three devices attached to the computer, plus a high end graphics card. It flickers like three times, for the three VGA connectors, and one time for the graphics card. Another assumtion is that I am using an adapter for the graphics card. My Windows 9x and pre-Vista machines does not do this at all, unless I hit the display utility ( the graphics card display devices, settings ). Again i assume it is Vista checking the display settings, and what is attached to it. It might also reset or go back to the "RGB please plug gerder" screen sometimes. It also happens when I use "Windows Classic" program in Vista, with a different color setting?