Notebook batteries are rated to last about 400 cycles, which typically means one year of standard use. However, I have seen them last longer. The precise amount of time you get out of a battery is dependent upon the usage & environmental factors.

If the BIOS is not detecting the battery the problem is either with the battery itself or the battery bay/motherboard on the system. If you have access to another system (same type) I would recommend swapping out batteries to rule out possibilities and also to see if the BIOS will detect it.

Try uninstalling Microsoft APCI-Compliant Control then reboot your system.