An improved method of testing a computer system comprises a sequence of tests that are performed when the computer system is first turned on, according to one embodiment. The operation of various components of the computer system, such as a chipset, a random access memory, a cache memory, a video controller, a keyboard controller, peripheral memory controllers, busses, and the like, is tested by a test program stored in read only memory (ROM). If the components successfully pass, an address is permanently changed in ROM, so that the test sequence is bypassed whenever the computer system is subsequently booted, saving significant time during future reboots. An improved computer system and a machine-accessible medium are also described.