System Date Jumps 1000 years

I have noticed on my system that the date will suddenly jump ahead 1000 years (2007 becomes 3007). I can correct it by adjusting the date and time, but it always comes back and it is random in the time that it takes to reoccur. The system can be idle or active, and it does not appear to be associated with any particular program. I have always used an antivirus (Norton) and Spyware Protection. None of which have been able to detect a virus or intrusion. I was wondering if anyone has had an experience of this nature and what can be done to eliminate it.
Your sage advice is welcome and appreciated.

Rocco Cambria