The Fetch-Decode-Execute Cycle is the fundamental process that a computer's central processing unit (CPU) uses to execute instructions. It begins with the fetch stage, where the CPU retrieves an instruction from memory, using the program counter to determine the address. Next, the instruction is decoded to understand what action is required. Finally, the CPU performs the execute stage, carrying out the instruction, which may involve calculations, data movement, or interaction with input/output devices. This cycle repeats continuously, allowing the computer to run programs efficiently.