Use this guide to replace a dead battery.
Push the black button and slide the battery casing to the left simultaneously, until the battery is completely separated from the device.
Remove the three exposed screws (4 mm) using a #0 Phillips.
Peel off the the sticker that says "Creative Warranty Void if broken" and remove the screw (4 mm) beneath with a #0 Phillips.
Remove the battery from the casing by bending the sides. The battery should pop out. Be careful not to snap the case.