voltage mod question

i have just done the cpu and chipset voltage mode
but i have one probleme here i cant set the cpu voltage more than 2.1 v
because mobo refuse to boot
my motherbord temp is 1c
and cpu 4c
using some extra cooling but why mobo dont bootif i set the cpu voltage more than 2.1v?
THANKS FOR HELp

There is an OVP circut that needs to be modded as well. ASUS MBs are such a pain to work with. I don't understand why they do not have all the voltage adjustments right out of the box.

OVP Circuit? what-the-who'z-it?