By any chance, is the oc Genie button pushed in? I've never used my oc genie button, but from what I can see, off the bat, is that it may lock down certain things in bios due to the board doing "everything" it self..
I'm not 100% on that factor, I'll search threw your manual some more, but that's what I can see just off glance..
BTW, welcome to TPU and if you can, please fill out your "system Specs" so we can help you in this thread, or in future threads.
Just tried oc genie, for the first time. I'm right on.. if you have oc genie, there will not be any manual volt changing in "cell menu"
Reason for it, the board is trying to oc for you. so, if you try yourself, you may lower it, and cause the system to be unstable. the chip won't know what to do and thus oc chip, could go out on you, and even corrupt the bios chip itself.
So, if that little blue button is on, oc genie, turn it off, and have at it in bios.. I'm locked out using it, and stuck now, till a download finishes again, at 3.5.. using the volts I use at 4ghz.. lol.