I was trying to install grub after changing hard drives by running and it complains that Why does it do this? How do I tell it which drive to install on to?

Welcome to LQ!!!

GRUB is installed on /boot why are you trying to install it on root lv or what exactly are you trying to do? What was the partitioning scheme before you changed the disk? When putting up a question it is always a good idea to give as much information as you can and what have you tried so far.

You did not mention which OS you were using? What exactly you did and what are you trying to do now?

Here is another thread where in someone had similar issue: http://www.linuxquestions.org/questi...-error-401582/

The thread is quite old, see if that helps else it will be good if you give us more information so that we can provide you inputs.