A prelit Christmas tree is a popular choice for holiday decorating, as it comes with lights already attached. However, issues can arise from time to time, requiring some troubleshooting. If the lights are not turning on, the first step is to check if the power source is working. If it is, then try replacing the fuse or resetting the circuit breaker. If the issue persists, check the wiring and connections to make sure everything is secure. If the problem persists, it may be necessary to replace the prelit string of lights.