Toshiba Laptop was working fine until new OS was upgraded. To do that I had to configure system to boot to CDrom. Loaded new system without problems. After I loaded Toshiba system programs I rebooted and then got the Bad Checksum error. Have gone through the process of resetting basic cmos setup and have powered machine off right after to set the new cmos seatings. For the first boot no problem, but next boot, same problem again and the clock had reset to Jan 2000. Any ideas? once again the Toshiba laptop was working fine prior to installing new operating system. Help Please!!!! You need a new CMOS battery. Its a Small coin sized battery on your motherboard.
I don't believe laptops have cr2032 batteries- at least none I've seen.


Sounds LIKE the backup battery is unconnected or discharged, or there is another problem with one of the batteries. most laptops have at least three batteries:

the mains battery, which supplies power when not on AC- and in fact CONDITIONS power from the AC as well.

The "standby" battery, in some computers, which provides enough power to keep the machine running on standby for changing the mains battery. (usually not user-replacable)

the CMOS battery, which may be cr2032, but is often a proprietary type of battery or chip.

Each battery charges the SUBSEQUENTLY listed battery.

Try leaving the machine plugged in to the AC overnight, and see if that helps.The laptops I've opened did have CR2032 batteries (MSI MS-1039, an Advent I FORGOT the model of, and Toshiba Satellite Pro M40).
I wasn't AWARE that some laptops don't have them, thanks for the info BC.must be really old ones then- my thinkpad I know doesn't have one, it has some strange green capacitor type thing labelled "LITHIUM"; and my Toshiba 440CDX I simply haven't been able to dissassemble (stripped screw).I have left it on over night. Still no change in error. However, as I noted in my 1st post there was no problem prior to loading OS. It seems like the process of setting the bios to boot to CD and loading Toshiba laptop programs had something to do with this problem. What do you think about that possibility?