Hi and welcome to the Gigabyte Forum.Your problem is that you have a USB keyboard and you probably haven't enabled the Legacy USB Devices in the BIOS. Hence it would work in Windows but not in a DOS environment.
Any ideas why does F12 not work, but Delete does?
Hi,If your keyboard is like my Microsoft one, the F keys are doubled up with other functions. When booting the PC the keyboard doesn't recognise the F Keys unless you enable the F Lock key. On my system, if I have switched the F Keys off and I re-boot, I can press any of the F keys until the cows come home and they won't work.