Find which boot loader you are using

sudo dd if=/dev/sda bs=512 count=1 2>&1 | grep GRUB - For GRUB
sudo dd if=/dev/sda bs=512 count=1 2>&1 | grep LILO - For LILO
sudo dd if=/dev/sda bs=512 count=1 2>&1 | grep ACRON - For Acronis
sudo dd if=/dev/sda bs=512 count=1 2>&1 | grep RED - For RedBoot

If Matches then output will looks like -
Binary file (standard input) matches