I will like to apologize on the problem at hand. But when you say to boot, are you getting anything on the screen or some error message, this is because you said that you were able to get into the BIOS.
Also please power off the system and remove the power cord from the system and also remove battery from the system board. And set BIOS jumper to maintenance. You can find the steps on the manual starting on page 52 (https://downloadmirror.intel.com/19926/eng/DZ68DB_ProductGuide01_English.pdf). Then try to power on the system. Then power down the system and set all options back to normal (jumper and battery). Then try to power on the system. If the problem persists please try to test the memory and the CPU on another system to ensure problem is not with any of this components.