Why my system can't boot after overclocking CPU Clock?

When overclocking the CPU FSB Clock, the memory frequency will also overclock at the same time. When overclocking make sure that you set the memory frequency to lower level, such that increases in FSB keep the memory frequency in a stable range. First deselect [Auto] for the "Memory Frequency For" as shown below. Try to set memory frequency to a lower level (ex. DDR 266 / 333).