That is a RAM read write failure (can also mean memory failure) and I assume it is connected to the OC you had changed. You can try to reset the BIOS. Remove the CMOS battery (coin cell) and leave it out of the system for 15 minutes (Intel recommends 30). Then reinstall the battery and try again. Hopefully that will reset the BIOS back to default values.You can also try to isolate the ram, in case only one RAM module is bad. Remove all but one module. Try to boot. If that does not work move the RAM to another slot and try again. If still no go then do the same procedure with the other RAM module. Also just to be sure that the SODIMM slots are not bad. Remove all RAM and try to boot, You should hear 2 beeps. That would at least seem to verify that the motherboard and BIOS are properly detecting no RAM and point back to bad RAM.
Worse case, the RAM will need to be replaced.
Also, why would the bios not post either way if the ram is just at an unstable clock. I have a hard time believing the ram is broken only because I never changed the voltage. Is there a protection reason for nothing posting and the laptop not auto switching back to the 2133 default clock?