I have a strange problem with Window XP. A computer that has worked
flawlessly for almost two years has suddenly started turning back the
date setting two years. The month, the day and the time is left
untouched, but the year is set to 2005 after each reboot. If I reset
it to 2007 and reboot the computer I can via the BIOS setup screen
verify that it is still 2007, i.e. it is at operating system load that
the change is made. If I switch to any year after 2005, it is set back
to 2005. If I switch to any year before 2005, it is left unchanged.

I have no idea where to even start troubleshooting this. Any ideas?