My monitor refresh rate, normally 85 Hertz, has recently started resetting to 60 Hertz on starting up the pc. I can?t understand why this happens. I have the latest monitor driver and latest NVIDIA graphics driver. It does not happen after every restart ? normally after two or three. The only things I have installed recently have been the Microsoft patches for XP released a few days ago and I can?t see that they would affect it. Any ideas?