I've seen such issues when upgrading BIOS version in boards like this with discrete graphics cards installed. You may want to try removing your discrete ATI graphics card and using just the onboard graphics, have another go at flashing the BIOS. If you get no video or action at all without the discrete graphics card installed then (leaving the graphics card out) initiate the Intel BIOS recovery method of flashing the BIOS and that should get you up and running again. Remember that you need to get it working properly using just the basic setup first before you slot your graphics card back in again.
If you want the safest way of performing BIOS updates, it's always with the simplest system you can possibly get it down to (ie all unnecessary USB devices, other peripherals and cards unplugged/removed from the board. Even then, if you have one, it's a good idea to power the PC through a UPS so that if there's a power cut, you are protected from killing your board with a currupted/incomplete flash. Let us know how this goes.