Looking at the BIOS file on the Acer download site for the G3620 (I cannot find AG3620) it appears you have an AMI BIOS. If that is correct, 6 beeps indicates a 'Gate A20 failure'. In short, this means the keyboard controller IC has failed. The resolution, of course, is to replace the keyboard controller.
Own a Predator Laptop? Then I bet you have learned a thing or two from beststevie. He has been helping out in this forum for quite a while and it's about time we recognized him for it. Thanks beststevie!