I had the EXACT same issue as you. Same GPU, same motherboard, same problem with the fan on the GPU whirling up but nothing being displayed on the screen. The solution is basically what the others have mentioned in this thread; uninstall all previous drivers. However, I also updated my BIOS first, which was really out of date, so I can't say whether it was old drivers or old BIOS which was the issue.
Check your BIOS version by pressing DEL on boot, and then go to advance and see what your version is. Mine was F10 and the latest (non-beta) is F22, so I was pretty out of date! You will need to do a Q-Flash by downloading the latest BIOS version and copying it to a USB. You'll need to extract the file, which creates three additional files, and then copy them to the USB, I got the instructions here (http://www.overclockers.com/forums/showthread.php/638325-Can-t-install-bios-update-64-bit-OS). Don't try and run the setup if you're using a 64 bit OS, it won't work.
Next, download AMD's clean uninstall tool: http://support.amd.com/en-us/kb-articles/Pages/AMD-Clean-Uninstall-Utility.aspx. I didn't have any of the AMD software installed, so couldn't uninstall using the control panel. This software worked a treat and removed everything.
Once I restarted the GPU worked as expected. I then used the DVD that came with the GPU to install the new drivers, then used the software to install the latest versions online. All working well so far, although I haven't done much other than the 'I can see something now' test. I notice you haven't commented in over a month, but hopefully this should help someone with the same, or similar hardware/issues.