As the thread title, my pc clock has started (in the last 3 days) running 20 minutes fast per hour. I've run an up to date virus check, rebooted numerous times, time sync'd with a server etc and nothing helps. does anyone have a clue what could cause this? It doesn't coincide with new software installations, my system isn't overclocked or anything and it has run fine for nearly 3 years with nothing like this. Even the IT guys at work are stumped.