I suppose checking the clock in the Bios is a good place to start. Is it current and updating? Usually when the clock seems to be not keeping time, it can be linked back to a bad CMOS battery on the motherboard. I am not sure if this is your situation, but if the actual bios time is incorrect, it could be.
I have seen some clock changes when I was dual booting with another OS. But I don't remember seeing any changes caused by third party software, but of course I don't run all of them.
Do you have your system set to sync to the Internet time, and can you get it to update manually?