Anyone know what could cause this? I have two towers I built that I switch back and forth on mainly to keep the antivirus up to date. This particular one when left off for a couple days lost 2 hours on the clock. This is also, the one that when I turned it on a while back it was so screwed up I had to run the win 7 home premium upgrade fresh install on it again. Any ideas would be a big help! Thanks.