i have a old p2 400. whenever i unplug the power out of the psu the cmos is wiped, almost as if there is no battery. ,i have tried this with 2 batteries, which i know both work
check the jumper on the MBD and make sure its not set to clear nvram, reset config data, or something like that. you may of cleared nvram once but never set the jumper back to nomral.
lol thats why I did to my grandmas intel motherboard.....anyone want an old ass intel board and celeron chip that was originally built by peoplePC like 4 years ago