Your right, one long beep and three short indicate no graphics card found.
When you setup the new board because you are using a 560 Gtx card you must check these.
The 24 pin atx block is connected, and the extra pci-e 12v power blocks are connected to the graphics card.
Most important is the extra 8pin 12v power block must be connected to the board from the psu. See the picture.
http://uk.gigabyte.com/fileupload/product/2/4516/8050_b...
The block is located next to the cpu socket.
If you fail to plug this in, then windows will fail to see the 560 card.
The eight pin does two things, it provides extra power to the cpu.
But also provides extra power the the Pci-e card slot of the board.
As well as the 12v Pci-e connectors into the card.
Or windows simply fails to see it and begin installing a driver or asking you to install one.
Check all of the above.
Then your going to have to reset the bios back to factory defaults.
Connect the video lead from the monitor to the on board video outputs.
Power up, now you want to be looking for and option in the bios that shows the order of what is the default primary graphics output device.
Eg: Pci-e, Peg, Igp
Set to Pci-e first in the list.
Turn off Igp.
save the settings in the bios and exit, power the system down.
Move the cable over to the back of the 560 card.
Power the system up.