My parents have this fairly old desktop with a core 2 duo cpu with 2 gigs of ram on top of an intel dg33fb mainboard. The problem with the machine is that quite often when the power is turned on, the bios throws a cmos battery failure warning and resets the time to 12:00AM 2006. I have tried replacing the battery, updating the bios firmware, restoring the bios configuration to default, but to no avail. Any help with this particular problem will be much appreciated.