As for the board being able to boot from usb, check the boot devices in the BIOS setup, you may need to set usb as first choice.
Otherwise, I see nothing on the Gigabyte site that would indicate that this is not possible.
Here is an video on how to install Win7 from a USB stick. LINK
You can google this and get more info.
Also, you could use an adapter and use the IDE drive on a SATA mobo, here's one.LINK