Make a bootable floppy disk with an autoexec.bat file. Also on that floppy you should have the .exe file for the flash and the actual .bin file that you want to flash the system with. In the autoexec.bat file, you should have one line that will go along the lines as such:
*.exe *.bin /?? /?? /?? or something along those lines.
The /?? are the switches that most award flash utilities have in them. Because you are dead in the water right now, you are going to have to find out what switches will allow you to automatically flash without interaction, reset the bios, clear the bios, and update the bios.
I have only had the way outlined by Damaged work one time. Who made the board? Is the bios chip soldered to the board, a little .75 inch square in a socket, or a .75 x 1.5 inch block in a socket on the board? If if is soldered, you are basically hosed. I have updated/flashed about 1000 system boards. With the advent of the programmable flash via software, I've seen quite a few botched ones, and I have had 3 recommended updates not work, only to find that the manufacturer knew there may be an issue with that flash, but didn't outline/acknowledge it until after a few people contacted them.
AOpen will have you send back the whole board, Abit will usually send you out a new chip - but they are a real bear to get to follow throgh. Each manufacturer has their own way of handling (or not handling) the bios issue. Tyan is one of very very few that will deal directly with the end-user as a standard part of their support.
Good luck and LMK