What does it mean when your system suddenly restarts without booting?

reset the bios, and hope you didn't fry it

if you need refreshing on that you are more than likely going to fry your MB or CPU overclocking that high. Slow down and do some research, it's your wallet.

the first part of any oc'ing project always goes easily showing a lot of gains for minimal effort. Then at the end you have to fight for every hertz.

oc's are also dependent on batch just cause one chip clocks that high doesn't mean your will, same goes for the mb. Further voltage has more affects than just heat, how good is your psu, what temps are you running, how fast are you increasing speed, at what rate did you increase voltage throughout your overclock because that will grow exponentially the further you go. O yes and lets not forget all the specs for the mem to....

research all aspects of what you are doing while mb and cpu selection are critical they but a fraction of the whole equation.