Ok, firstly, calm down. There's no use in getting all worked up over something little like this.
Secondly, if the worst comes to the worst, Gigabyte should take back the motherboard and replace it for you. You did nothing wrong, right? You didn't stop the BIOS update process or anything, right? Just ring them up, make sure you're covered, and you'll just have to pay for shipping the motherboard to their warehouse (AFAIK).
Thirdly, do you get any power though the computer at all? Fans spinning? etc... Any beeps? Try reseating the RAM (use different slots, too). Pull the power cable out the back, then take the battery out for 2 mins.
Fourthly, I am sorry that this has happened to you over my instruction. I read on a number of topics that people have had the best OC results with F7. Sorry for any trouble I have caused - however, at the end of the day, you do take a risk when overclocking.
P.S. Don't mention you were trying to overclock if you end up having to send the motherboard back to Gigabyte...
