Did you set boot order as CD , HD , whatever ?
Did you check that system sees CD and HD as it should ?
I have 3 DVD burners and it seems each of them burns it's own brand
although all will work on DVD Player for example.I would advise burning
to CDRW or DVDRW as it tends to have better compatibility.
If you manage to boot from CD you need to use VESA mode.
Also , I don't think that system will boot from usb.As a last resort ,
you can try installing windows xp just to see if computer works then
install aros.
Icaros only needs CD Drive and burned CD image to boot and
you will be able to run it from CD with "HD Install option".If you
are not getting that far then something about configuring IDE
drives on Gigabyte motherboard is wrong.Maybe jumpers ?