My computer is running XP Pro 2002 with out service pak. My clock is always 5 minutes behind and since the daylight change 1 hour 5 minutes. If I adjust the time to the correct time, I notice it will change back and be 1 hour and 5 minutes off again. Do not understand why it changes and it will do this at no piticular time. It may take 5 minutes to change or 3 hours.