So long as you don't go too high on the voltage, you really can't screw anything up, all that will happen is that the system won't POST, after which, you'll have to clear the CMOS.
First thing you want to do is get a program up and running that will tell you the voltage that the cpu is running at. Then run a benchmark program or stress test(preferably a cpu benchmark, as that pushes the system harder) and see what the voltage is at(this will give you a starting point for when you take manual control). Write the number down. Go into bios, save the current configuration as default or stock or some such name. Then go into the part of your bios(I've not used your mobo, but it is a good mobo for over-clocking). Find the cpu VCore voltage, turn it off auto and set the number to the number you wrote down. Save this bios configuration to a new save spot and title it "test" or some such thing. At this point. Go back to VCore and lower it by a small amount(say .015 volts). Save the config in your test save spot. And re-start the system. If it posts, that's grand. If it doesn't, go back and add some voltage back(it almost certainly will post). Let windows start and run one of you stress test/benchmark programs(a lot of people like prime 95). Run through it for a while(10-20 minutes). Re-start the computer, go into bios, save the configuration to a new spot, call it "Known" or some such thing(this is the spot you use for configurations that you've tested and that pass). Lower your voltage again(say by .01volts this time). Save the config to the test spot in your bios saves. Go back to windows and re-test. Keep doing this until your system either doesn't POST or your system crashed doing the stress test. You'll need to clear the CMOS after this, and then re-load your last configuration that passed the stress test. After you do this, go into windows and run much more extensive tests. Run a bunch of bench tests and stress tests, and run something for a while(an hour maybe). If it passes, then go back to the bios, and save a final configuration and call it "optimized" or some such thing. If after doing this, you get any crashes of the system, you'll need to go into bios and add a touch more voltage(say .01volts).