Key differences between a laptop and a desktop computer involve their design, portability, and performance. Laptops are compact and portable, enabling users to work on-the-go; they typically have integrated components such as keyboards, displays, and webcams. Desktops, on the other hand, offer greater power and upgradeability due to their larger size, allowing users to customize components like graphics cards and processors. Performance-wise, desktops generally have better thermal management, leading to enhanced performance during resource-intensive tasks. Ultimately, the choice between the two depends on the user's need for portability versus performance capability.