System Crash with message failed to open \efi\redhat\grubx64.efi

I am having trouble starting my system. Whenever I try to power it up it fails with this message "failed to open \efi\redhat\grubx64.efi" Believing that this problem is related to grub I tried to rescue the system using a rescue mode from bootable USB drive. I followed the procedure described here (https://access.redhat.com/solutions/1521 - Reinstalling grub2 on to MBR). However, when I tried to install grub2 using the command grub2-install /dev/sda1, I get the following error "cannot find EFI directory". Any suggestions on how to re install grub2 ?