A quick confirmation of the battery type (CR2032, which is apparently the nigh-universal CMOS battery), a quick glance in the motherboard manual re: the error messaage, a quick run to Fry's, and Voila! No More Error.
Grand total: 60 cents and the remains of a Fry's gift card with $1.55 on it.
*This does not mean that Horrible Catastrophe is not Looming to strike, without the courtesy of prophecy. Remember: "No boom today. Boom tomorrow. There’s always a boom tomorrow. … Boom, sooner or later. Boom!"