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.
Member RevoMaxx is quickly moving up the ranks of Acer Community. He joined us in September and is already making a difference. It's great to see new members like him make a difference only after a few months. Thanks RevoMaxx!