The battery only gives power to a cmos ram (RTC: real time clock) that holds config data used (read and write) by the bios, if you have done an upgrade of your bios, it is stored in an non volatile memory (the flash or eeprom that stores the bios itself) so, your version is the latest you have upgraded.
I agree with others about that the battery is dead.
When you remove the battery, a capacitor near the chip still has charge enaugh to power the cmos ram for a while, so only removing the battery will not clear a password, for example.
Always is better than you insert the battery with the cmos ram unpowered, so first do a short between the 2 pins of the jumper (with a screw).
Edit: I'm sorry, there is a jumper near the battery, if set, only removing the jumper, will cease the power from the battery, but a capacitor holds power for the cmos ram, so if you want to be shure that the memory is unpowered and lost all the info, remove the jumper caps and do a short.
Juan
I agree with others about that the battery is dead.
When you remove the battery, a capacitor near the chip still has charge enaugh to power the cmos ram for a while, so only removing the battery will not clear a password, for example.
Always is better than you insert the battery with the cmos ram unpowered, so first do a short between the 2 pins of the jumper (with a screw).
Edit: I'm sorry, there is a jumper near the battery, if set, only removing the jumper, will cease the power from the battery, but a capacitor holds power for the cmos ram, so if you want to be shure that the memory is unpowered and lost all the info, remove the jumper caps and do a short.
Juan