compaq armada cmos battery

I'm working on a Compaq Armada. I've replaced the CMOS battery, which is just 6 cells with a 2 pin connector to the motherboard. the time and date are working,but after 2 days, i turn it on, and resets back to january, 1980. I've replaced it twice and both times, after 2 days will reset to january 1980. I've tested the 7.2 V battery and its at 6.4 V. something is draining the battery is my guess. is there a way that i can figure out what is causing this?

Does it have any warranty left?

When ever I have come across a system that the cmos battery is being drained that fast I just replace the mainboard. Cheap to do on a PC, not so cheap on a notebook.