It’s pretty straightforward to upgrade from grub (legacy) to grub 2 (version 1.96) or later. Just be cautious that when running grub-pc, one needs to choose a proper device (by UP or DOWN or SPACE), even if you only have one hard drive. Otherwise it will cause error 15 and a boot failure. I think this is very import and should draw much more attention than it does now. But somehow the grub2 developers didn’t think that way. And I am one of the woeful users who learn the error 15 the hard way. 
The good news is that it’s not so hard to fix the boot failure. You need a live CD, chroot to your hard disk, sth. like this
$ sudo mount /dev/sda1 /mnt$ sudo mount --bind /dev /mnt/dev $ sudo mount --bind /proc /mnt/proc $ sudo mount --bind /sys /mnt/sys $ sudo chroot /mnt
And reconfigure the grub-pc. And you get rewarded
This is one the default images in the debian repository. (grub2-splashimages), also my current splash image.
