CMOS Battery Replacement

Hello: I got a 2008 Dell Inspiron 530. I want to replace the battery CR2032. Getting on boot after be down for a couple of days. Does anybody know for certain whether that year (2008) and model if the battery is only keeping internal clock running when computer is down or the CMOS information is held by the battery and is lost when replacing battery. If I write CMOS information what information do I write.What sections? Dell Owners manual says write down or print out (how) the setup information. No details other than that! I’d rather be safe then sorry!