Ok, multiple issues with my PC. Configuration : P4, 845 GV motherboard, bios version VA84510A.8GA.0023. P08 1. It switches on directly on stwitchin on the mains(without having to press the power button on the CPU) 2. On turning it on, it displays the message : "CMOS/GPNV checksum bad. CMOS Date/Time not set" (changing the battery didnt help) 3. The monitor(SAMTRON) keeps giving the message "Control lock locked/unlocked" intermittently. 4. Also get"CPU was previously shutdown due to a overheating issue" message, once in a few days. I have 2 Hard disks - 40GB Samsung(Primary) and a 250GB Seagate(additional) I installed SpeedFan and it shows me that the the seagate hard disk gets heated very fast, often reaching 50 deg celcius withing an hour or 2.

""CMOS/GPNV checksum bad. CMOS Date/Time not set" (changing the battery didnt help)" After you changed the battery did you access the BIOS & correct all the settings? "I installed SpeedFan and it shows me that the the seagate hard disk gets heated very fast, often reaching 50 deg celcius" The system temp & CPU temps are what's important...what are they reported as?

Even after changing the battery, the time is not saved and is reset to Jan 1 2002 each time it boots. I do not know what setting to correct in the bios. I did do a "Load optimal defaults" but it made no difference. SpeedFan shows me only the HDD temperatures. Perhaps there are no sensors for the CPU temperature.

"Even after changing the battery, the time is not saved and is reset to Jan 1 2002 each time it boots" Did you verify that the battery is good? Actually, the battery is only necessary for when the power is completely switched off to the tower. If the tower is turned off but there's still power to the PSU, the motherboard is still "energized" thru the +5VSB (SB = Stand By) & the BIOS settings *should* be retained. That's why it's recommended to unplug the power cord when resetting the BIOS via the ClearCMOS jumper. "Perhaps there are no sensors for the CPU temperature" Did you look in the BIOS, possibly under PC Health or something similar?

So what preceded all this? Did you have a recent outage or power spike? From your described symptoms above, I suspect your PSU as part of the problem.

are you sure the cmos battery jumper is a)in the correct position and b) is not missing altogether. The PC starting when you plug the power cable in is probably due to a bios setting, something like 'after power failure' the setting is not set to 'Always OFF'

Can someone please explain in detail, how to go about "resetting the BIOS via the ClearCMOS jumper" ?