I noticed there was some flickering with my monitor on my HP computer when I was still running Vista.  Check in your display settings to ensure that the refresh rate is what it should be.  THe refresh rate for my monitor is 60Hz.  When I turned on my computer, it would set the refresh rate to 25Hz, interlaced.  When I set it back to 60Hz, the flickering stopped.  You can find this in the advanced options in display settings.

JB