>- Check that your screen refresh rate is not 60Hz. This can cause occasional beat frequencies with fluorescent or incandescent lighting

For those types of monitors, they are all locked at 60Hz now. I have an Acer 24 inches with a video card ATI Radeon HD 4600 Series.

>- Check for an updated video driver

I am ok with that.

>- Fire up Task Manager with nothing running, on the Processes tab watch for 5 minutes ordered by CPU usage (descending) until you see which process spikes (goes to the top of the list momentarily)

I will perform that task on the next reboot.