Changing the CMOS battery on the motherboard

I'm learning more troubleshooting skills. The problem is that the troubles are hardware problems and aren't directly related to things I'm supposed to be doing for the Unit assignments. Nevertheless, I've identified some online help for how to replace the CMOS battery:

http://www.computerhope.com/issues/ch000239.htm
and
http://www.ehow.com/how_8159_change-battery-computer.html

I also got out the Dell Dimension 8300 Series Owner's Manual and it gave similar step by step instructions.

Now I'm going to go buy a replacement battery.

...The battery replacement was successfully completed and my workstation is working as it should be (so far, so good). For whatever reason, it is much quieter than it had been! (We blew out a lot of dust from inside the machine. Maybe that has something to do with the noise - or lack thereof now.)