hi gLk*zaP
It may be your memory as clunk suggests,but
It sounds similar to issues i've been having occasionally, although i have an OC on.
My solution is as clunk says try with 1 stick.
i've been able to boot then getting the oc failed message.
I've found that once i can post, i can add back my 2nd stick.
Subsequent memory testing/orthois produces nil errors.
It will run fine for a while then it will recur occasionally when rebooted.
Our symptoms are also described here Asus P5K-Deluxe: Flashed BIOS - Boots Fine but "NO SCREEN!" Post 10 is similar solution to what i'm having to do.