Small BIOS problem

I have a Compaq Evo N1020v laptop and this is my problem: the battery is dead for a while now, but every once in a while (I tend to think it's everytime the laptop stays disconnected from the AC power for more than 10 hours), the BIOS resets itself I've already replaced the small CMOS battery and still nothing when I said the battery is dead, I meant the big one, not the CMOS ... what might cause this ? It's frustrating to have to setup the BIOS daily

did you test the wires that connect the SMALL BIOS BATTERY to the motherboard? they could be cut or circuit is cut therefore the battery cant give full
voltage.

how did you know the bios reset itself?
1) date in bios changes to a very old year
2) pop up message says press f1 to continue
3) the screen displayed a big fat man running naked

people dont answer dificult questions here, you need to make the question simpler or ask (how do I type the @ sign?) then millions will answer you

thats weired!

if the date stays the same then its not resetting itself because the bios battery, the bios itself is doing this
what exactly is it resetting?