Final answer:
The nurse should first check for a pulse.
Step-by-step explanation:
The first thing the nurse should do when noting a total lack of normal electrical activity on the EKG monitor is to check for a pulse in the patient named Billy.
Checking for a pulse is important because a lack of normal electrical activity can indicate a potentially life-threatening condition, such as ventricular fibrillation, which requires immediate medical intervention. By checking for a pulse, the nurse can assess if the patient's heart is still beating and determine the appropriate course of action.