The Dell XPS 15 is a powerful laptop that is built with high-quality components, but like all electronics, the motherboard may need to be repaired or replaced over time. The motherboard is the main circuit board in a laptop and it houses the CPU, memory, and other components that make the laptop function. The process of repairing or replacing the motherboard on a Dell XPS 15 is complex and requires technical skills and special equipment. It is recommended to seek professional help or to contact Dell customer support for guidance. If you are experiencing issues such as the laptop not turning on, random shut downs or blue screens, it may be time for a motherboard repair or replacement.