MemOK! is a proprietary technology on ASUS motherboards that automatically adjusts memory parameters on the motherboard to correct boot failures caused by memory problems. When users fail to boot due to failure to adjust memory settings or memory overclocking, or other compatibility issues, simply press this button to automatically resolve the issue.
Did you set the memory overclock in BIOS to fail to boot? We recommend that you restore the factory settings in BIOS and then reboot the machine and it should be fine!