Answer - The layers of Windows XP system boot-up is as follows: - A situation of operating system portability is created by the hardware abstraction layer by hiding hardware differences from the operating systems upper layers. A virtual machine interface is provided by the hardware abstraction layer to be used by the kernel dispatcher and the device drivers. - The foundation provided by the kernel layer is used by the executive functions and the user mode sub systems. The kernel would always remain in memory and cannot be preempted. The functions of the kernel are thread scheduling, interrupt and exception handling etc. - The executive layer is responsible for providing services to be used by all subsystems. These can be object manager, process manager, i/o manager etc.