A physical bulge under the trackpad is a classic CompTIA-identified symptom of a swollen lithium-ion battery. As batteries degrade, internal gas buildup expands the casing, pushing upward on the laptop chassis-often distorting the trackpad, keyboard, or bottom shell. This can cause cursor issues, clicking problems, and safety hazards.
Replacing the battery first is essential because swollen batteries can rupture, leak, or ignite. Only after the battery is removed and replaced should the technician evaluate whether the trackpad suffered permanent damage.
Replacing the trackpad (D) without addressing the battery fails to correct the root cause. The motherboard (A) and heat sink (B) are unrelated to the physical bulge.
Thus, the correct first step is replacing the battery.