where is the CMOS battery for a Dell Venue 8 Pro?

I've researched where it is for this specific tablet PC and only came up with the 11-in version and other motherboards that have a coin-like CMOS battery, but the 8-in Dell Venue Pro does not have this item. Someone mentioned on some other forum it could be a button. I need to reset the button or remove the CMOS battery to clear the BIOS password which is not working anymore. Cannot get past that password prompt after factory-resetting Windows. Please help.