View Full Version : BIOS checksum error

18-06-2006, 02:24 PM
After upgrading one pc, I put the old Mobo and CPU into a new box for my daughter but it wont boot. Comes up with a message saying:
"CMOS checksum error - defaults loaded.
Warning! CPU has been changed or CPU ratio changed fail.
Please re-enter CPU settings in the CMOS setup and remember to save before quit"

That's what I can't figure how to do.

The Mobo is a VIA P4PB-400 FL fitted with a Pentium P4 2.4G CPU and 1 x 512 DDR 400 RAM (new). The box came with a 450 watt PSU, and at the moment, that's all that's connected - no drives or peripherals. The board and CPU combo were working fine on a 350 watt PSU before.

In the Bios setup, the only relevent page seems to be "Frequency/Voltage control". The options for the CPU with current settings are:

CPU Vcore select.............Default
CPU clock.......................100

It says that the current CPU voltage is 1.5volts

There is a setting labelled "CPU clock ratio" in the manual, but it doesn't appear on screen.

If I go to the BIOS Settings page "PC Health Status", the Vcore is shown as 1.48v.

Can anyone shed any light on what's wrong and how I can possibly fix it please? Could I have damaged anything during the transfer between systems? I'm pretty careful about ESD issues and have checked all the jumpers and switches. I have reset the Bios to no effect.

18-06-2006, 02:37 PM
Maybe your CMOS battery is flat?

Also the VIA site says the instructions for clearing the CMOS were wrong in the original manual..

18-06-2006, 03:11 PM
Thanks, but the battery is okay - I swapped it just in case but to no avail. Ditto with the power supply - new one made no difference. Strange thing is, if I make any change at all to the bios settings (or even no change) and do a "save and exit", the machine will not boot at all again until I clear the Bios settings again, and I did know about the error in the manual thanks.