Press F8 whilst booting to bring up the Boot menu (you may need to press it a number of times to make sure you get the right moment). From here select "Enable VGA Mode". You should then boot up with a reduced resolution (640x480). You can then adjust the resolution of your video card from Desktop Properties. Change it to 640x480, reboot and then adjust it again. If the display doesn't show for a resolution that you pick, wait 15 seconds and it will revert to the current setup.
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